To say that "no one is oppressed" because athletes are a diverse group is a bit superficial. I would suggest that our society's willingness to put athletes on a pedestal certainly helps people of color overcome the prejudices that undeniably exist and that would limit their opportunities, were they not stellar athletes.
We have decades of what is intended to be equality under the law. That has been a great thing and something to be proud of as a country. Go USA! But equality under the law doesn't necessarily mean absence of oppression and equality of opportunity.
Someone (Maya Angelou?) once that said that sometimes progress, while welcomed, falls far short of sufficiency. Limits are still there. As an example, say that black people can attend the school dance, where they cound not before. Then whites all declare that the problem is solved, without noting the policy that black people attending the school dance can indeed get inside the door, but are still forbidden from walking onto the dance floor. In that scenario, what was accomplished?