What are the causes of Anti-Zionism?
This is a complicated question because the answer is complex and can become inflammatory quite easily. The following are answers given by various WikiAnswers users speculating why people hate Israel. These views are not necessarily endorsed by the people who gave them, and are certainly not endorsed by the WikiAnswers site. These answers are sorted by category.
1) Fear of Antagonizing Others: Some people are afraid of supporting or legitimating Israel because they fear another terrorist attack from another country that is less sympathetic to freedom of expression. While Israelis, and Jews in general, are used to people trampling on their ideals and not bombing public places or threatening mass death, other groups are more prone to such activities.
2) International Legal Violations: Israel has engaged in a number of policies in violation of international law, such as the unification of Jerusalem, the settlements in the West Bank, the annexation of the Golan Heights, etc.. Israel is not reticent for performing such acts and claims that it violates those laws because they are prejudicial to its rights and interests. If other countries did the same, (Iran is a great example), they are sternly reprimanded by the international community and forced to toe the line.
3) Anti-Semitism: This should be self-evident. The Logic goes thus: Anti-Semites oppose any Jewish aspiration to freedom and/or power. Zionism promotes Self-Determination for the Jewish people which is an aspiration to freedom and power. Therefore, Anti-Semites oppose Zionism. Additionally, many people who are Anti-Semitic see Jews as running some sort of international cabal to strip power from everyone else. Equipped with a country, who knows what further havoc Jews could cause. The Arab World is prone to these types of conspiracy theories, making the Protocols of Zion and Mein Kampf bestsellers in the Arab World. There are many respectable Arabs who take these works seriously as historical discussions of Jews.
4) Palestinian Indigenous Rights: The indigenous Palestinians and their descendants are aggrieved that people from abroad would come to the land that their parents, grandparents, and great-grandparents had lived on and worked for as long as they could remember and buy that land from the Ottomans without consulting them. Moreover, these people had a particular agenda to establish a state on the land they called their own. Understandably, the Palestinians, and those who support them, are opposed to the Zionist project for these emotional and political considerations. Additionally, the Israeli Military Occupation of the West Bank Territories and the Blockade of Gaza represents a true legal and humanitarian crisis for Supporters of an Independent Palestine and the Palestinian People. To many people, the Palestinians must have the right to go back to their homes (although it is doubtful that the Arabs would have permitted that right to the Jews should the Arabs have been victorious in the Arab-Israeli War of 1948-9).
5) Jewish Reversal of Dhimmi System: The Arab class system during the Islamic Empires had always been very clear. Muslims were of a superior class to the non-Muslims (usually Jews and Christians) called Dhimmi (which means protected ones). This is coupled with the Islamic assertion that once a land comes under Muslim domination that the land should not convert to non-Muslim power. A small minority of Muslim Revanchists make claims at controlling Spain, which was only ruled in parts by Muslims for 700 years over 500 years ago. Israel sits on lands that were under Islamic domination for nearly 1300 years (with a less than a century under the Crusader States). Therefore, many Muslim Arabs rejected the Jewish state purely because it was Jewish. Had it been just another Muslim group, a separate state would have been accepted without controversy, like has been the case for the 22 other Muslim Arab states. But it was intolerable to allow the Dhimmis to set up a state, especially one in which Dhimmis would rule over some Muslims.
Some information on the discrimination against the Dhimmi: The Dhimmi was required to pay a number of taxes that were connected with his dhimmi status. The most famous was the jizya, which was a tax that Dhimmi had to pay for Muslims for the right to not be killed where they stood for not acknowledging Mohammed's Prophecy; it was a form of humiliation. Additional taxes included the kharaj, which was a tax on non-Muslim land-holdings in the Muslim World. The kharaj was so untenable that most Dhimmi were forced to live in the cities where the tax would not be applicable. On paper, a Christian or Jew could testify against a Muslim, but in reality, such testimony was not acceptable and the attempt to "defame" a Muslim would receive retribution. Christians and Jews were not allowed to build new houses of worship, restore old houses of worship, proselytize in any way (this included religious debate or dialogue), or allow wine or pigs to be shown in public.
6) Arab Nationalism: Arab Nationalism as a movement crystallized in the 1930s and came to the political fore in the 1960s. Arab Nationalism is a movement that seeks to create an Arab State or multiple Arab States based on common cultural and historical markers. This movement began to make a tether between Arab cultural identity and Islamic religious identity. This was especially keen in places with large non-Muslim communities because those communities typically worked closely with the European colonizers seen to be repressing the Arab identity. Zionism, which is a movement based on a European cultural identity and a Jewish religious identity was antithetical to the Arab Nationalist movement ideologically and claims territory that Arab Nationalists also claim putting them at odds politically.
7) Islamism: Islamism, the political philosophy that Shari'a or Islamic Religious Law should be the grounds upon which a state is ruled, strenuously opposes any Western-style of government because it does not uphold Islamic moral standards (for example: gays and haram meats are permitted). Israel, as a secular, Westernized State is opposed for this reason. Israel, specifically, is also hated by Islamists for two reasons unique to Israel. The first is that the Jews are the ones in power. In the Islamist conception, only Muslims should be in power in the State and any non-Muslim minorities should have a secondary role if they should have one at all. Second, Israel is situated in territory which used to be governed by Muslims for nearly 1300 years (with a century-long break under the Crusader States). As a result, Israel is considered a usurpation of historical Islamic authority whereas European countries (for example) never had Islamic authority before.
It is worth noting that not all Muslims are opposed to the State of Israel and there are several Islamic arguments in favor of the State of Israel, such as those advocated by Sheikh Hadi Palazzi, Irshad Manji, and Tawfik Hamid. None of these individuals, though, is an Islamist. Of the Muslims who oppose the State of Israel, not all of them are Islamist either, many are Arab Nationalists or have no general political affiliation and oppose the State of Israel for one of the many other reasons listed here. Finally, Islam/Muslim/Islamic is the religion and Islamism/Islamist is the political philosophy; the two are different.
8) Anti-Colonialism: While Arab Nationalism was an anti-colonial movement, the general principles of the anti-colonialism led to a rejection of States based on European values in non-European locations with a large number of non-European (ethnically speaking) inhabitants. This sentiment was felt most strongly towards (South) Rhodesia, South Africa, and what would become Israel. Anti-colonialists believe that Asians and Africans had the right to Self-Determination pursuant to their cultures. However, Rhodesian and South African institutions could and did eventually convert to being African nations (in the true sense of the term) because their racist infrastructure could be reformed. Zionism is by default a government by the Jews and would cease to be Zionist if the Jews were taken out of the leadership position. Thus Zionism catches the ire of anti-colonialists.
9) Political Antagonism: If State A has a lot of wars with State B, State A and B will develop a mutual animosity towards each other and their raisons d'être. There are a number of politically independent or partially independent Peoples and States that came into conflict with the Halutzim (Jewish Pioneers in the British Mandate of Palestine), the Haganah et al. (Jewish Militias), and Tzahal (the Israeli Army). This has only increased with the numerous Arab-Israeli Wars, the Intifadas, the Occupation of the West Bank and the Blockade of Gaza, and Israel's acquisition of nuclear weaponry.
10) Anti-Nationalism: In today's world, as things like globalization, cultural diffusion, and mixed ethnicities in major districts become more prominent, the Zionist model of a Nation-State dedicated to one race or religion seems anachronistic. Germany, founded on the same model, now has the issue of integrating Turks (and their children) into the German state, but since Germans always lived in Germany and constituted a majority there, as opposed to being a reorganized Diaspora, nobody suggests that Germans should "return" to a more cosmopolitan type of existence. This is, however, oftentimes suggested by Anti-Nationalists and Post-Nationalists concerning the Jews and their State.
11) Non-Jewish Holy Sites: Since the Holy Land does not only have Jewish Holy Sites, but also has Christian and Muslim Holy Sites, there is opposition in these communities to Jews having a physical monopoly and control of these holy sites. Therefore, these communities opposed the idea of a Jewish Nation State that could do exactly that.
12) Jewish Blasphemy: There was a prevailing belief among the more religious Jews (Orthodox, Hasidim, Ultra-Orthodox, etc.) that the Galut (the Exile from the Holy Land) was a divine act of punishment because Jews had violated the commandments that God had given them. When God believed that the Jewish people had repented and were ready for the Messiah, this Messiah would come and bring the Jews back to the Holy Land. Until that time, Jews will remain in exile. The Orthodox and some branches of the Hasidim and Ultra-Orthodox eventually came around to supporting the State of Israel, but not on the grounds of it being a Jewish (religious) State. They typically support it because it is a nation with a large percentage of Jewish people. However, there are some very vocal factions in the Hasidic and Ultra-Orthodox communities (such as Neturei Karta) who see a Return to the Holy Land as being an act of blasphemy because Jews should wait for God to bring them into the Holy Land and not to physically move there of their will.