Is hate based upon religion or is it the other way around? If I would have to guess I would say that hate existed for longer, religion just providing a fertile ground since we are taught not to question our beliefs. The biggest problem seems to lie in interpretation of ancient scriptures, a topic which will probably never get one definite solution. But limiting the amount of interpretation possible could be a viable alternative. With the new testament the bible already had a first cleansing of hatred, maybe it is time to write a second revision which aims to completely erase any harmful preconceptions built in by the writers. Because as long as the hate is still in there, someone will be able to use it as a tool for their own goals. Do you think it is possible to construct a belief that can’t be twisted the wrong way?
To touch upon another topic I am not sure if the Holocaust is the best example for utilizing religion — there were quite a few resistance movements whose existence depended on churches. Hitler saw religion as a tool, but also as a dangerous threat to his plans that would eventually have to be brought into line or destroyed.