They're not compatible in YOUR opinion. In my opinion they are. Both countries were full of people who wanted independence. Both countries saw USSR as a bigger threat to them then Nazi Germany. As tragic as the Holocaust is, normal grunts like you and weren't aware of it, so it was completely irrelevant to the decision making. Both countries needed help against their enemy. Both went to get help from the enemies of their enemies.

Nazis were bad. But at the time we didn't know that. It was just another country. We can take lessons from that about being pickier about our allies, but at that time, to those people, Germany just seemed like someone who could help against the Russians.