An exam question for religious studies students in Britain briefly broke the taboo against explaining anti-semitism:

"Explain, briefly, why some people are prejudiced against Jews."

The education secretary was quick to disown it:

"To suggest that antisemitism can ever be explained, rather than condemned, is insensitive and, frankly, bizarre." 

http://www.guardian.co.uk/education/2012/may/25/michael-gove-jewish-exam-question

Not only is it unscientific to claim that anti-semitism can never be explained, it is also dangerous. If you want to avoid its terrible consequences ever happening again, it might be worth trying to understand why anyone, anywhere, could be 'prejudiced' against Jews.