There is a hierarchy of acceptable deaths in the gaming world. The safest bets are robots, and families have enjoyed slaughtering billions of them with not the slightest moral code bent.
Next come zombies, which are incredibly popular as bullet sponges. It's okay to kill them because they come pre-killed. You're doing them a kindness, really, as their headstones clearly read "rest in peace" rather than "lurch forever in search of brains."
Nazis are first on the ladder as acceptable live human cannon fodder because they've got the all-time award as The Worst People Ever.
Being absolutely indefensible scumbuckets does that to a movement.