John is one of eight mech pilots heroically protecting Earth from an alien invasion. Pretty easy on the moral choices. See evil monster from space, kill evil monster from space. Only then he actually meets one of them face to face.

Karkat is all for cultural exchanges and trying to see each others point of view, but there is such a thing as going too damned far.

"You've got no fucking clue which end is up about this kind of thing, do you?" Karkat asks, almost gently. "I'm sorry, I shouldn't have gone off on you. You're such a huge bitch it's easy to forget you weren't hatched like this."