Embracing something labeled "Gay culture" is kind of aligning yourself very strongly with an identity defined by your sexuality. Of course when you know people they don't seem to be all encompassed by it, but when you are actually getting to know someone you are starting to deal with them on a level greater than broad sweeping stereotypes about their culture, so obviously it is hard to see how that is entirely defining someones identity (Of course it generally isn't that all encompassing). The thing to remember here is you are talking about Labelling Theory here, the more precise the analysis of a subject the less generalised the labels have to be, so you give them more labels in a big pile.
You can see it in this very discussion. You start with Gay Subculture, and then you go on to cover how there is multiple ones, Bear, Daddy, Twink, Flamer, Whatevers and so on. And... when you get down to it there is some people that have some overlap there, so they need more labels and there is some of them that have regular day jobs, so you give them another label. Some of them like Ice Cream as well.
But from the distance, the one that stands out is the Sexuality, it might be because the person isn't hanging around and fucking ice cream quite so prominently in their social hours. Pretty much it just comes down to Sex is one of our biggest most widely bandied around Labels and for a good point, it is one of the most easilly determined, so it flows through to sexuality and things related to Sex and Gender. It is a fairly straight line.
It is all still a bullshit social construct and something that needs to be broken down better so that more people can easilly remember that they are talking about people and not a pile of sticky notes.