I’m on the fence if the reply is ruining the joke, as OP clearly wrote the last sentence as the punchline

Let’s assume OOP is an openly gay dude. That’s why he has a profile pic on grindr (implied). The dude who’s hounding him doesn’t.

Suppose OP is roommates with a woman.

Suppose that woman is in a relationship with a guy who’s bi/curious/closeted and is hounding OOP because he’s seen him while visiting her.

That would make sense.

But I think it’s just a punchline