Surveys show that at least one fourth of gay men never have anal sex, only oral sex. And of course lesbians don't usually have anal sex.
Heterosexuals do however, have anal sex. Since there are a lot more heterosexuals, most of the actual anal sex acts being performed are done by heterosexuals. Yet homophobes always bring up anal sex, icky butt sex, fudge packing, etc etc when they attack gays.
I wonder if this might explain rabid frothing homophobic posters on the Internet and for that matter odious politicians. Right before daddy penetrated mommy vaginally he had her anally, and a little poo ended up in the mitochondrial DNA in their zygotes.