Are they on athletic scholarships? If they are, they have contracts with the university, so they either play or they need to figure out a way to pay for their education.
I would certainly send them and their families a full bill for this semesters tuition the very first practice that they missed.
If blacks don’t like majority white schools, why don’t they just go to the black colleges. You don’t see whites going to black colleges and then crying about racism and demanding that the president be white. Let them sit it out. It only hurts their futures with the NFL which is what they all want to do.