pixie
Some more maths.
If there are 160 out professional sports stars, and the number of gay people in the world is 2% of the population, the statistically speaking, there are few out gay people in sport! both as an absolute number and as a proportional number.
I do not condemn gay people for staying in the closet if they are in a field where they feel it would be disadvantageous to be free to openly date who they want, but it must be galling for many who see their straight friends openly dating, getting engaged and marrying out in the open, whereas gay sportspeople who wish to remain in the closet have to sneak around living in fear that at some point they'll be exposed by one of the tabloids.
When you say that straight people don't announce their sexuality, I, afraid you're wrong. They announce it all the time...implicitly - by dating members of the oppose sex, marrying, having affairs etc.