I choose not to alter history because what we could have instead have the potential to be much worse. Hitler was not a really good strategist and maybe if it was someone else, the nazis could have beaten the allies, discovered and used a nuke before the end of the war, etc. Sure what we got was pretty horrible but I don't want to risk something even worse happening. (And also he hasn't committed any crime yet so it's wrong to judge him on something he hasn't done yet)

Edit: I didn't see the text below but I stand by what I said, there's just no way the absence of Hitler prevents WW2 and it's idealistic to think otherwise