I don't think our genetically-motivated in-group preference has changed much.

No. But our global connectivity and laws against interracial relationships have changed a lot.

But mostly evolving independently. You can't say that Japan wouldn't be racially affected if it became 25% Haitian all of a sudden.

You're right; I can't say that. But that's not a problem because I haven't.

That all sounds logical. When talking about race I never just considered melanin content, though.

You are not the arbitrator of races. Racism as a formalized pseudoscience goes back centuries and your personal opinion on what the races are has no bearing on what racism actually is. It has always been about physical appearances, most importantly the color of skin.

If you want to classify the Andamanese people as members of the (it still feels wrong to say yellow) Asian race to make the genetics line up with the races then you are revising racism.