Sports were associated with masculinity, strength, and power traditionally inherent to men.
The whole history of professional sports development was associated with men: women were not allowed to participate in Olympics until 1900 and were accepted for a very limited range of games. The reason why homophobia is so widespread in sports
It turned out that wide audiences still stay homophobic, and it seems to takes too long for most people to become tolerant towards male and female queer individuals.