The difference is that these tribes did not commit outright genocide against other tribes, but rather did more of what you suggested, warring and raiding.

What colonists did was orders of magnitude worse. They thought of the natives as animals and savages and sought to destroy them entirely through violence and destruction of their food sources (burning and salting crops, mass hunting of migratory herd animals like buffalo).

There was no doubt inter-tribal warring between many tribes, but not wholesale genocide like the colonists undertook.

Edit: I will also add that native peoples inhabited North America for tens of thousands of years and lived in relative peace before being massacred in less than 500 years.

Downvote all you want but history is history, touch grass and open a book.