It shouldn't be the main deciding factor, but it helps. It's a signal like any other, although because it's superficial, it might be something you pick up on earlier.
Most people aren't driven to just one career path in life. They start out with a few different options that narrow as they get older. Given that, if you are investigating two careers, and they both have lots of creative tinkerers, but one of them has many more people that match up with your race and gender, is it unreasonable to factor that in to your decision?
White people don't have much historical evidence that they will receive poor treatment in the NBA or the jazz community because they're white. But black people and women do have reasons to pay special attention to signals that they might not be well received in a certain community/industry/workplace. It's not their fault for being aware of that.