They're still 4x games since extermination is always an option, even if that's not the path you choose to take to win. It's pretty much a mandatory victory condition in a 4x title.
In addition, I again refer back to
Anguille's comments on starting conditions.
It’s been a while but I don’t think there’s any exterminating in eu either - Austria will always be Austria it’s just a case of who owns it
Aye, but games like Stellaris and DW:U don't require you to exterminate anyone. So should those game be disqualified from being 4X
you don't have to exterminate anyone in a Civ game, but it can be cathartic to do so
Also, this.