[Blackacre]

Let's say that Hitler won the second world war, would gassing Jews be considered evil ?

Depends. If the Nazis conquered the world and were able to basically brainwash everyone into their ideology, then gassing Jews wouldn't be considered evil. But such an outcome was never really within the realm of possibility.

[SeekAndFind]

If the Nazis conquered the world and were able to basically brainwash everyone into their ideology, then gassing Jews wouldn't be considered evil. But such an outcome was never really within the realm of possibility.

I gather from your response then that the answer is YES -- Nazis, if they could successfully do what they do are NOT intrinsically evil, just different.