Answer 1
Many people consider the "outsiders" inferior. Jews also have a history of fighting against discrimination as they have been terribly victimized throughout their history.
Answer 2
This is a misperception that comes out of the Jewish idea of "chosen-ness". Many non-Jews see it as Jews believing that they are superior to non-Jews as opposed to how Jews understand it. The Jewish understanding is that the Jewish people were charged with a distinct mission/task that the rest of the world was not assigned and this is to elevate the spiritual character of the world. This charge is very similar to that which monks and nuns take on in Catholicism and nobody chastises them for this act because we understand the hardship that comes out of that level of dedication. Jews are compelled to be so dedicated.
(Another more pop-culturally modern version of this is the idea of the "Fellowship of the Ring" in the "Lord of the Rings". The members of the Fellowship are in no way superior or better than the rest of the inhabitants of Middle Earth, they just have a specific task to which they have been assigned and upon which the entire world depends. People outside the Fellowship are more than capable of helping this mission which some (like King Theoden of Rohan and Faramir of Gondor) certainly do. It is just that the onus of responsibility lies on the Fellowship.)
Many Jews consider Israel to be their homeland.
If you consider yourself Jewish but do not follow Judaism, holding to no religion at all, then you are a "secular Jew". A significant proportion of Jews are secular Jews. Some Jews have adopted a form of Christianity and consider themselves Christian Jews or Messianic Jews.
all kinds of them, even some who did not consider themselves Jews (but had Jewish parents or grandparents).
The fact that he left sending them to concentration camps till last may indicate that at some level he knew that they were harmless.
Some certainly did and converted to Islam. However, those Jews who remain Jews will accept the right for Muslims to profess Islam, but will consider those views incorrect for themselves.
Almost every kind of people besides "Aryans" (Germans, but also Scandinavians, English, Dutch, and some French) were considered inferior. However, besides Jews, the Nazis in particular hated Slavs- Polish, Russians, Serbs, Bosnians, Ukrainians, etc. This is a big part of the reason why Nazi Germany invaded Poland and the Soviet Union- the Nazis wanted to kill or enslave the Slavs, and settle "Aryans" in their lands.
Some were religious and Orthodox Jews, some were Reform Jews; some held no real religious convictions, some were atheists, some had converted to Christianity, some were the children or grandchildren of mixed marriages who were now 'tainted' in the eye of Nazism. They were all doomed.
Spam
It was about a popular belief of the early 1900's. Many "progressive" political and religious leaders of the time believed in a concept called "eugenics". It wasn't just a German thing, although Germany actually took it a couple steps further, and implemented a program that embraced the concepts of eugenics. Eugenics is the belief that the gene pool was being negatively affected by what they called "inferior" people. The theory suggested that inferior people should not be allowed to breed, and if possible they should be eliminated. That would include mild to moderate learning disabled, any form of handicap and of course, the Germans decided that Jews were inferior as well, so that Hitler could fund his military. The idea about the Jews being inferior made it easy for Hitlers Germany to kill 6,000,000 Jews, taking their money and property, and using the proceeds to fund their war. Today we know that not only are Jews not intellectually inferior, (some of the best doctors, lawyers and scientists are Jewish), we also know that the feared destruction of the gene pool is not taking place.
Some Jews live in Israel.
They held the Jews responsible for Germany's hard times. The Nazis thought Germans were part of a "superior race," and inferior people should be killed because they were holding back the superior people. This is actually a theme that is repeated frequently throughout history, whenever some people decide that they are better than some other people, no matter the reason.
Some schools' vending machine sell inferior quality food for the kids to get higher profit.