I don't think everyone agrees that being gay is not a choice. There are no outward physical indicators of a person's sexual orientation. It's entirely behavorial and therefore plausibly under the conscious control of the person. Now, I would agree that a person doesn't choose which gender he is attracted to, but it not something than anyone else can see and immediately understand as an inborn characteristic.

Clearly being black, or hispanic, or asian, or white are physical characteristics. Far fewer people would argue that there is any element of choice in that.