Another part I forgot. Money, like yall already mentioned.
MMA is an expensive sport to train and compete in. And plain and simple, in general, blacks make up more of the lower class. I've played baseball and football my whole life. In baseball, It's rare to come across a black guy. You have to furnish your own equipment which is costly. Football, the equipment is provided to you by the organization or school, so they can afford to play it. And basketball, all you need is a ball and goal, not too costly.
"Hope dies last"