Their polities weren't then part of the US polity, so they'd have a separate we. Now they are part of the US polity, so they could include themselves in that we.

But to honestly answer your sarcastic question: There were a bunch of them, and they typically didn't include their fellow natives in their collective understanding of "we" until later years. At the time, and even prior to colonization, various tribes did indeed commit, or participate in, genocide on other tribes. Just like the pseudo-collective "Europeans" did among their tribes.

Some history:

https://en.wikipedia.org/wiki/Crow_Creek_massacre

https://en.wikipedia.org/wiki/French_and_Indian_Wars#Indigen...