I know one factor is that people who born in Germany where raised from childhood not to question a order or a person in authority. So when hitler came to power he had entire nation willing to accept any orders he wanted. So when the nazi government says it is permissible to deny the Jews their rights and then says it is imperative to exterminate the Jews they comply even if they where friends and neighbors for years. What a horrible terrible chapter in history where people allowed their own hatreds consume them. I really believe without Josef Goebbels being such a good propaganda minister I don't think the message of destroying the Jews as a whole would have gotten to the masses as quickly as it did. He roused everyone's hatred to the max.