I imagine most of the people who think futa is gay have never interacted with an actual homosexual person, at least nothing deeper than hello and goodbye. Because otherwise they'd know... actual homos don't give a shit about futa. And honestly that's pretty intuitive, if they're gay, why wouldn't they just masturbate to two dudes going at it? Bear or twink, doesn't matter, even the most effeminate men found in porn aimed at gays will be very distinguishable from porn aimed at fetishistic straight men (stuff like traps and so, that steer more towards homosexuality or bisexuality than futa).
Funnily enough, a fag I know has a fetish for... cuntboys.
As stupid as it may be, I like discussing this topic. It's a shame that usually anti futa dudes can't hold a civil conversation and start sperging out everywhere.
I have more takes but I'll just leave this here
https://youtu.be/p-A8GvUehq4