This question has been dealt with in the FAQ. You can see answers here: http://www.reddit.com/r/AskHistorians/comments/1005c0/what_caused_jews_to_be_hated_so_much_through_out/ and http://www.reddit.com/r/AskHistorians/comments/1izufd/why_have_jews_been_persecuted_by_so_many_groups/ and http://www.reddit.com/r/AskHistorians/comments/1niu47/why_are_jews_so_hated_historically/ plus http://www.reddit.com/r/AskHistorians/comments/rncuh/how_come_its_always_the_jews/ and don't forget http://www.reddit.com/r/AskHistorians/comments/1b1z2x/why_was_there_such_hatred_against_jews_before_and/ but wait there's more: http://www.reddit.com/r/AskHistorians/comments/1eey2u/why_were_the_jews_discriminated_against_outside/