I know straight guys who love pop girls and buy their albums and support their music. They don't keep up with their personal lives or whatever, but just love the music. They even go to the tours, and I can tell you they're fully straight. Everybody just likes different things; doesn't make them automatically gay.
However, if you're referring to the concept of "stanning", then that shouldn't be limited to just gay men, cause trust me, you'd be surprised. Personally, I find the concept of "stanning" unhealthy, but that's just my opinion.