What region was the holocaust?
The Holocaust itself had no religion as it was not a person, but the perpetrators were Christian and the victims were Jews.
I don't see how anyone could possibly compile reliable statistics on that. What's more, a lot of people would feel under an obligation to give a 'good answer' and that would vary from region to region: in the US a 'good answer' to 'Do you doubt that the Holocaust took place?' would be 'no', but in much of the Middle East it would be 'yes'. To cap it all, in many countries, the reply would…
There were a multitude of reasons. It would be misleading to promote the political reasons before the practical, but best to say that the conditions during the war and the political ideology at the time combined with the history and percieved history of the region came together to create an atmosphere that allowed the Holocaust to happen.