I don't usually use 'evil' to describe things but I don't know any other word to describe settler states and their tendency to massacre and torment people they stole their land from and gleefully brag about all the horrific atrocities they've committed/want to commit. Never before have I seen a group people that take more joy in the suffering of others than the kinds of people that want to wipe out entire societies and claim their land for their own.
This is the kinda shit where if you write villains that act exactly like this people will slam you for bad or unrealistic writing, but no, it would actually be perfectly in line with reality all things considered.
EDIT: ps I know me not good at writing things. Wish I can write my thoughts on this better, but I can't really get it into right now
Fundamentally - There are people everywhere, and there have been for tens of thousands of years. We keep pushing back the date when people arrived in NA (per European science, Indigenous people have their own accounts). There are only a handful of landmasses in the world that haven't been settled for at least 1k years or more.
So, if you're going to colonize and settle somewhere there are already people there, and they're in the way, and you're going to have to do incredibly cruel and violent things to take their stuff and exterminate them.