They were hated because they were Jews employed by the Romans to collect imperial taxes levied by their oppressors; a tax the Jews always chafed under (Matthew 22:17). They were considered to be traitors. (It should be understood that these tax collectors, who are equated with "sinners" several times in the New Testament, had nothing to do with the "temple tax" collected by the Jews.)
Jews hated tax collectors, as they were Jewish people collecting tax from the Jews for the Romans.
Some antipathy would naturally arise even if the tax collectors just collected what was due - no one likes to pay taxes... But the Romans allowed tax collectors to add their own charge to what was owed - sort of a "handling charge." The amount they added was unregulated, but still backed by Roman military might, so some tax collectors were actually robbing the citizenry. Because of this, tax collectors were widely seen as a thieving class.
I'm assuming (since the question is posted under the religion section) you are referring to the tax collectors in the Bible. The answer is yes. The Jews did not like tax collectors because they a) represented a foreign government and foreign leadership and b) took their money. Stories from the Bible like Zacchaeus show the generally poor opinion the Hebrews had of tax collectors. In other passages, Jesus is criticized by the religious leaders for associating with tax collectors and sinners.
The whiskey boys hurt the tax collectors all the time.
the king maybe
Matthew was a tax collector and by that occupation was shunned by most people. Tax collectors were viewed as traitors because they worked for the Roman government. Probably most of Matthew's acquaintances were fellow tax collectors and then when he became Jesus' disciple his main acquaintances were his fellow disciples. By being a tax collector, Matthew was helpful to Jesus' ministry to other tax collectors.
They were tax collectors and judges.
We're not allowed to hate anyone except those who despise God.
There were two tax collectors one was Matthew and the other was Zachaeus.
You need to specify where and when in history men attacked tax collectors if you want to make it possible to answer this question.
The Sons of Liberty tarred and feathered tax collectors as a form of protest against British taxation policies. This violent action was meant to intimidate tax collectors and discourage them from carrying out their duties.
A tax collector in ancient Rome was an "exactor".