@Flaxmeadow
Something to think about, maybe, is that it was not that long ago that different sorts of Europeans largely thought of each other, and spoke, as if they were different races. To be a French person was quite different to being English, or German, a different kind of person.
Wasn't this more by nationality than race.
The idea that Europeans saw themselves as racial different seems to be more an American thing
No. National identity to some extent was seen as being built on race. The French weren't seen as different because they belonged to a different nation - they were a different kind of people, with a different character, different temperament, different language and history, even a different look.
But that is the thing - race is whatever people say it is. There have been all kinds of scientific attempts to define race, but in the end you really can't because it's defined by arbitrary lines where really there are only variations across a large spectrum of characteristics.
Race emerged into this idea of white and black fairly on in the US in order to separate what had earlier been a mixed slave population of varied origins, so you ended up with a divided underclass. Sources of European slaves were drying up anyway, and it had become clear that there was a real danger in an underclass that saw itself as having mutual interest in changing their circumstances.
So whiteness and blackness, as concepts, were invented to categories people into classes based on a fundamentally arbitrary set of physical characteristics chosen because of economic convenience, specifically to give a certain kind of value to each group.
All Critical Race Theory does is try to invert that, it doesn't challenge the concept at all. Which is why white suprematists find it a useful tool.