The not-so-famous John Amaechi, former NBA player, has come out and admitted publicly he is gay. I am struck that he is (only) "the sixth professional male athlete from one of the four major U.S. sports — basketball, baseball, football, hockey — to openly discuss his homosexuality."
Those are scant numbers, why? I see a few hypotheses:
1. There aren’t so many gay professional athletes, maybe because guys play college ball to get women.
2. Even the not-so-famous earn endorsement income, at some level or another, or at least hope to, and that implies a mainstream image.
3. Fans don’t want to see gay players, or at least they do not want to know too explicitly about sexuality in that manner. Major league sports are about numbers of fans, not the possibly intense minority loyalties that could be generated if a major star came out of the closet.
I put most of the weight on #2. When it comes to #4, my sense is that the teammates often know or suspect who is gay, even if it is not publicly admitted.
Keep in mind it is relatively easy to measure performance in sports. The real lesson is that employer-driven discrimination is no longer the dominant model.