People hate jews because for so much of history, they have been "the other". In christian American and Europe, this was the case for many centuries. In the middle east, the simple fact that they where not muslim meant persecution, and with the independence of Isreal this only gave them a very specific, very public target for their hatred.
In modern secular America and Europe, the perception by the political left that Isreal is somehow the new nazi germany, that has invaded the mythical land of "palestine", makes jews a safe target, like christians, men, and heterosexuals. This combined with the recycled "theories" of post WWI anti-semetic politics of the jews as the "evil bankers who financially destroyed the country", I think contributes largely to the massive rise in antisemitism in recent times.
Of course that's just my ignorant, one sided, non college educated opinion.