I’m not sure how “racism is bad” requires the idea that “we are all equal by nature”.
“Racism is bad” means that the law should treat us equally and that you should not treat people differently based solely on their skin color.
So if you see that e.g. one group is lagging behind in math then that is taken at face value as evidence that 'math is racist.' A search for that exact phrase will turn up a million hits, pushed by some very big entities, if you want to go down this rabbit hole.
But if you don't already know about this stuff - just don't. The amount of stupidity and transparent divide+conquer politics in it all is just nauseating.
On the other hand it does have contemporary relevance as a lot of the funding for this stuff is being scrapped, and it's nice to understand what we're 'losing.'
But the ties to racism do seem inane and more to do with outrage culture becoming the norm after the social media explosion. It’s unfortunate.