Whether or not someone of any gender is curious about, wants, fantasizes about or takes part in anal sex in any way doesn't tell us a darn thing about their orientation. Human sexuality is incredibly diverse, and all someone liking a given kind of sex can usually tell us by itself is that someone likes that kind of sex. And for all of these groups, all of that goes for being on either end of anal sex, as it were, and for people with partners of any or every gender. There are also heterosexual men who like or love it. There are heterosexual men who don't like anal sex or aren't interested in it, either. But there are also gay or bisexual men who don't like it, or who just aren't interested in it.
There are gay or bisexual men who love or like anal sex, it's true.