I think we’re talking at cross purposes. My list isn’t intended to be a list of things that only straight people do. I’m in a gay marriage myself, so I’m perfectly aware that gay people can have spouses, children, etc. My point is exactly that gay people should be free to mention all the things on the list in just the same way that straight people regularly do (in programming communities and many other contexts).

As for why people bring this stuff up, I think that reduces to the question of why people make small talk. I don't know, but they do.