Black people aren't expected to like sports, OP.
1. Y'all are genetically blessed when it comes to athletics, people tend to gravitate towards what they're good at.
2. The majority of professional athletes with big personalities are black. We live in the social media era, athletes are celebrities. Black kids see themselves in these public figures and wanna be like them. They're role models.
3. You're influenced most by who you spend the most time with. If your friends are all into a sport and you see them having fun and getting female attention out of it, then chances are you'll try it out. Plus men are competitive and physical by nature. Sports pray on our instincts - humans evolved to be physical and social, not sit in front of a screen for 12 hours a day.
This isn't all black kids. Some of y'all like anime. too.