I wonder where this movement started where people overly obsess about this

Evolution.

As a toddler you form your “in group” based on the people you see. Mostly that you are actually around, but also just exposed to on TV.

Anyone that you’re not exposed to is “out group” and you can use conscious thinking as an adult to include others in your ingroup but when you get old and lose mental ability you’ll fall back into “did I see people like that as a kid” distinction for “us” vs “them”.

For the vast amount of human history, if you ran into a group of different looking humans, they were a competitor and you either boned them or killed them.

People want to act like 10,000 years of human society makes us better than other animals, but that’s a blink of evolutions eye, we’re still animals and if we’re not socialized we’re gonna act like animals.

Can’t we already just treat people for who they are/their personality and not judge them by their skin color and also not prefer some ethnicities over others?

We do that by integrating society and children’s TV with integrated casts of diverse people.

Which is why conservatives and even some moderates opposed things like school busing and Sesame Street.

They’re not picking random shit that doesn’t matter, they’re planning decades in advance to make sure the next generation can be manipulated into thinking along racial lines rather than realizing there’s no just war except a class war.

Quick edit:

We can see it in modern day with the obsession of preventing kids from learning LGBTQ is a thing, they want kids to form their “us” group as just heterosexuals so that when that generation grows up they’ll view anything LGTBQ as “them”.