This is something that goes back at least 2000 years and there probably is no single answer to your question. Among those who today "hate" Jews are Arabs and other Muslims due to the very recent history of Israel coming into being and the conduct of their governments, military, officials and some of their ordinary people as part of land issues and their interaction with the Palestinians.
Going through the many historic examples of spectacular anti-Semitism one might suspect the issue is one of mistrust of groups that never quite fully integrate and intermix with their neighbours plus very likely an additional envy over the success, material and otherwise, that many Jews achieve/enjoy. In other words, an us-and-them phenomenon.
Conversely, the public stance that Israel, Israelis and other Jews take, whenever challenged regarding the Palestinian question and other smaller issues, is to play the Holocaust card and (to a lot of people) milk that argument for all it is worth. Some people feel that is eroding/reducing support for the obvious sentiment which correctly puts the wrongs of bigotry, persecution, etc., including anti-Semitism and the rest, as indefensible, unacceptable and unforgivable.
This is not a simple matter/question and it has parallels regarding other groups.