We were all humans untIl....
Until our numbers grew and we had to compete for resources. Until agriculture came along and made it possible to increase our numbers even further. Until religion came along and pitted one group against another because of a desire for one tribe to be superior to another.
I don't believe people are different from one another but I do believe a part of evolution is the need to survive and we do whatever we need to do to that end.
...and until war made us into us-and-them. Great! 5 ways to de-humanize!
Well so we are not humans anymore but we got 4 ways to group ourselves now.
Heh. I feel like you are poking the tiger here (raises paw).