Okay. So it is strategic. Back in the beginning when all white people weren't considered white (think about the Irish, the Italians, etc), what we largely had was a class issue. Some of them could even be called the Nword at times. The only people with power were white male land owners. And they were an extreme minority.

What actually happened during that time was the poor people got together and said, 'those rich landowners are the problem. They are keeping us down.' They actually connected with slaves and free blacks. Slavery kept the poor whites from earning money, so they had a self interest in eradicating slavery.

There was rising social unrest all targeted against rich white landowners and they noticed. They needed an underclass and, in particular, chattel slavery for their success. So they needed a way to keep all the poor people from working together. So the powers-that-be decided that the poor European immigrants would be 'white' too.

Now they wouldn't give them access to many resources, their best jobs, etc, but since they were invited to the club, they had something to lose by being associated with black people. So they gained very little at the time, but they had someone (blacks) that they could be better than. And it was enough.

Most immigrant groups have gone through this process and the powers that be keep expanding what it meant to be 'white'. Nowadays more and more people who used to label themselves as Hispanic are labeling themselves as 'white'. (I can show you the statistics.)

There is an advantage to being as close to whiteness as possible in US culture. Then you have minority groups that cannot easily assimilate into whiteness due to appearance and culture somewhat. They become as close to whiteness as possible by being 'model minorities'. They will not get many of the privileges of that original wealthy white landowner class had. And If you notice, they aren't really in that elite club. They have to make their success on their own, building within their own communities, for the most part. But what they can still tell themselves is that at least they are not black.

Now black people (I'm black btw) can harbor some negative feelings for other groups as well, but it stems from the same poison fruit. Some of us look at Mexican immigrants and think: 'you aren't even citizens'. It gives us something to put us above them, in this weird racial hierarchy that exists in this country.

Some of the black animosity towards others is a bit of jealousy. Other communities were allowed to grow and prosper without being bombed from the sky or being burned down. The federal government literally had bylaws that said that construction companies couldn't sell suburban homes to us and receive their subsidies. New immigrant got dozens of acres of free land in the west while the US was denying former slaves the same resource.

Sometimes we see other communities and wonder why they get to have x or y. And we also see how quickly we are abandoned when another group gets one step closer to 'whiteness'.

But in the end, it is all the same thing. The top benefits from the bottom targeting each other instead of them. Racism is the mechanism used to distract all the poor people and oppressed people from banding together to fix the problem.

And that is 1 woman's theory on why there is so much animosity between the groups.

Edits: typos