Why are people of mixed ethnicity disproportionately underrepresented in positions of power and influence within society?

So I wonder why to this date on a high level of things like the corporate world and even in the media you still mainly see white/caucasian people?

Like when I think of CEO's, boy bands or movie stars I rarely see for example black people. I feel like they're under represented and it needs to change.

I once asked a similar question on a different Lemmy account and they were telling me I'm racist for being against racism. How does this make sense? I'm pretty sure white supremacy is a real thing and I think it's important to speak up about it. Why do you think this is still an issue? Do people not care about it?