As much as the trans movement likes to indulge in homosexual-erasure/appropriation, what you describe seems counterintuitive in its extremity. It would mean a belief that every homosexual is trans, which I doubt is a widely held enough belief to bother with

Trans cracktivists don't say every homosexual male is trans, just that a lot of them are. And it's a widely held enough belief that I think it does warrant attention. A very similar belief is even more commonplace amongst young lesbians today, which is why lesbians are becoming rarer than hens' teeth.

Re gay men, prominent UK author Juno Dawson has publicly said

there are a lot of gay men out there who are gay men as a consolation prize because they couldn’t be women.

Dawson’s comments were defended by fellow trans writer and activist Shon Faye, who wrote, ‘It’s not homophobic to say some gay men are actually trans – I should know, I was one of them.’

According to these guys, being gay is merely a half-way station for many TIMs. Not all gay guys are really trans, they say, just a lot of them.

https://www.gaystarnews.com/article/juno-dawson-gay-men-consolation-prize/