Your claim is that racial disparities occur due to racism. I'm pointing out that it's not necessarily the case and giving you a blatant example. So white men aren't as good at sports and therefore makeup only a tiny percentage of the leagues. Maybe this same concept applies to other areas? Maybe black people just have little interest in some of these places you've noticed disparities?
As a woman I can tell you there is nothing stopping women from going into STEM. When I did my minor in computer science I was one of two women in the core classes. I wasn't discriminated against. I was allowed in and treated fairly. Other women just didn't appear to be interested in it. So the gender disparities in STEM could easily be due to a lack of interest, but feminists will tell you it's sexism. I believe that's total BS.