We can be evil if we want to.
But I don't want to side with the evil guys. This happens every Arms Race game, they always end up committing war crimes and siding with the most evil people they can for the most trivial of advantages. At this point I know I can't stop us from siding with them, but I want the record to show I fought this as best I could.
What are we going to do when Japan asks for assistance bombing pearl harbor? What are we going to do when Germany asks us to send bombers to help hit civilian targets? What are we going to do when the end of the war rolls around and the Allies start hitting us with war reparations? And before you say "this is alternate history" think; do we really want the Axis to win?
Those are terrible examples. When The nazis ask for our jews, then we have a problem, but we probably have appalling census data and couldn't find them even if we wanted to. We don't even know how many Foreinians are currently in orbit...
As for Pearl Harbour? We do the same thing we would for firebombing Tokyo, or stalling the communists so that U.S.A. can finish the bomb before Japan falls. And Germany may have formalised the bombing of civilians at London, but the Allies redefined it with the carpet-bombing of pretty much everything. And The Nazis were just ordinary people, caught up in an ideology that seemed like a good idea at the time. I am confident that many people you know would have been Nazis if they had been in Nazgul Germany. And let's not forget that one of the great arguments for joining the Allies was that sitting by and doing nothing while evil spreads is amoral failing. That is exactly what the Nazis claimed, and they had no shortage of conviction nor courage in taking on the whole world in order to rid it of evil. Now, granted, they had some EXTREMELY dubious ideas about the nature of evil but had they somehow been correct then they would have been tragic heroes. In my experience the closest you will ever come to a legitimate use of the term "evil" is to describe something that believes that it has the authority to proclaim that something else is "evil". Everything else is just various flavours of mistakes and a general lack of consideration.