You do realize that multiple native groups obtained their land through war and what at times could be called extermination?
The Comanche are but one example. There are very few groups in history that ended up where they were peacefully. That's unfortunate, but depicting the European settlers as land-hungry thieving murderers should take into account that's what everyone did.
Here's an account of the Fort Parker massacre, which wasn't uncommon on the frontier:
Benjamin Parker was killed, and before the fort's gates could be closed, the raiders rushed inside. Silas Parker, who was outside with his brother, was killed before he was able to get back inside the gate. Samuel Frost and his son Robert were killed inside the gate, as they attempted to flee. John Parker's genitals were cut off and he was then scalped. His wife came out of the woods when she saw his torture and was captured.[5] Lucy Parker and her youngest two children were initially captured but were rescued by Luther Plummer as he ran up to the fort from the fields. Her two oldest children, however, along with Luther's wife (Rachel) and son, and Elizabeth Kellogg were successfully kidnapped.
https://en.wikipedia.org/wiki/Fort_Parker_massacre
Did those settlers deserve that? You can argue it, but this is a complex topic. Maybe some of those militias existed for good reasons, like if they didn't, people would get murdered by raiding parties, as they have in every locale in history.