Can't we keep the "closet case" thing in the closet?

I wish people wouldn't do this:

I’m betting Mr. du Toit is a closet case.

I am, as you might expect, not a big fan of the post she is denigrating. But the practice of claiming that people who make anti-gay remarks must be "closet cases" has to stop. First of all, it partakes, however slyly, of the notion that calling someone homosexual is a slur. Second, it's unlikely to be true; gay men (it's almost always said about men) are only about 3-5% of the population, and a lot of those are now out. The remaining closeted gay men are vastly outnumbered, unfortunately, by the number of men who are intensely uncomfortable being around other men who do not like to sleep with women, even if they are doing something that doesn't involve women at all. And third of all, it's a warmed-over remnant of 1970's pop-Freudianism, which is to serious psychology what Scientology is to science. The underlying theory of aversion formation makes no sense when applied to any other context--would anyone seriously entertain the notion that people who are uncomfortable around racial minorities secretly fear that they are black?