I just think its fascinating that you're willing to judge "The slaves" as a hegemonic group but when it comes to people of a wealthier position in society and with a paler complexion by comparison suddenly you want to stipulate on all these individual actors
Show me where I judged the ex-slave children or the ex-slaves that didn't partake in the massacres.
You're talking to a straw man.
Also I'm not saying the slave owners were justified; I'm saying they would be justified under the moral precept you were proposing.
We're all already mutts made up of a bunch of extinct progenitor races and you have to travel to some really fucking isolated places to find anyone who shows signs of being racially pure on the genetic level.
If everybody was equally mutted, then the word would have no meaning. If people are mutted to different degrees, then the word does have meaning.
Just because it's easy to push people to purity spiralling doesn't negate the underlaying meaning of the word or that a more balanced perspective of it is possible and sensible.
People who bitch and moan that everybody is going to look the same in the future seem to be ignoring the fact that we've kind of already reached that stage.
No, we haven't. For the majority of people it's not hard at all to judge, even at a glance, what continent the majority of their genetics is from.
edit:
Here I'll take a step back and show why.
You always have to use the right level of magnification to look at a problem to solve it. The point of race isn't to draw a line and sort every single person into one or the other. They're intentional broad categories and there are going to be people who are so close to that line that it's not really sensible to sort them wholesale into one or the other.
But with that said, there is still value in the classification. For example, we don't remove all names of colors, red blue green yellow, because they're all the same and they exist on a continuous spectrum anyways. There is value in being able to name the colors of the rainbow. To designers, there is value in more precise granularity, so they use words like mauve, aquamarine and other color names that make my head spin.
Now then of course is the next question, I think you've said it: "What's the point of mentioning the differences?"
Well, first of all, simply looking different would in itself be point enough. If people look different, they are going to be treated differently. If you don't believe that to be the case, go and travel to a country where nobody looks like you, particularly if you leave the capital and go more inland. Every time you go out on the street, people will stare at you.
You can't sweep that difference under the carpet. If you do, you remove the fundamental basis for being able to combat racism itself. If we together would all pretend like there aren't visible differences, then we also can't claim to be treated differently based on visible differences (and we are).
Now of course there's a lot of other consequences and they're worth discussing too.
I think that people that are curious about whether such a concept of race (should) exist or not, should watch this Norwegian documentary (you can turn on subtitles).
It really is both entertaining and informative as a Norwegian comedian interviews various people, mostly academics. Then he let's those academics respond to his interview of the others. Very entertaining and some people get properly rustled. The show is called "Hjernevask", which means "Brainwash" and it's a series about topics that are taboo in contemporary culture.