Gemini men just want to talk dirty?

Those are called f***boys. Don’t mistake them for being “men”.
Back to your question, Gemini men love to flirt and explore all possible options.
I see them enjoying open relationships etc.
This is why they usually pair them with Sagittarius women.
But this doesn’t mean they’re hopeless. I see them enjoying an intellectual informative conversation. They love to learn.
They’re also funny when it comes to telling their stories and adventures.
Try to drag them to talk about one of those.
But remember, they’re not your loyal Scorpio

Astrology is fake.

Strictly your point view. Astrology is magic and no statistics exist for magic.

Well, it ISN'T only the men with Sun in Gemini.

I'm a Gemini and I love talking dirty, but its not something I must do, nor do I do it all the time because there is a time and place for everything. But you do have a point. If you don't like talking dirty, then I suggest you just avoid Gemini men, lol.