2 dudes showing PDA. Really any PDA makes me cringe but 2 dudes has always grossed me out too much to not turn away. Have gay friends, best friend has a gay dad, Im eskimo brothers with a former chick who was a dude waiting to have the surgery to be a dude before any gender related shit was making headlines, I also worked for years as both a chef and a male nurse that gave me a higher than average exposure to gay coworker dudes compared to other industries I've worked in. I love them all and love(ed) hanging out with any one of them but when it comes to actually seeing the gay shit, I can't do it. I gotta turn away or see what's going on in other rooms. Seeing a dude and a chick or 2 chick's is more roll the eyes kind of cringe but the 2 dudes is more of a physically grossed out feeling. If that's homophobic then fuck it I guess I'm homophobic.
I don't feel this way about dudes kissing or PDA, but if I accidentally click the wrong link or scroll past a thumbnail with some explicit gay porn, I feel the exact same visceral disgust.
That's how I OG confirmed I'm not gay back in the day. Trying to watch gay porn and having my dick shrivel like a frightened turtle; wanting nothing to do with it.
If you're interested to work on this within yourself, of course getting professional help with a therapist would be best but you could also try some simple exposure therapy on your own. Maybe watch some shows and movies featuring normalized gay relationships. Use that to slow-drip the normality of gay PDA's existence into your experience.
Here's a Rotten Tomatoes list you could browse to get started. I think you might want to look for stuff where you can follow and enjoy the plot as well as see gay characters showing PDA. You can try doing this at your own pace to work on slowly desensitizing whatever cringey bit in your mind is having these homophobic reactions and messing with your ability to deal with public reality.
If you are interested in this idea I'd suggest sticking with mainstream films and avoiding porn. Even though it's really available and even if porn in general is your thing, porn generally isn't the best way to constructively work on your own sexual education. I think since it's PDA you're dealing with you'd be much better off with stuff that can teach your brain about the human side of PDA in our society, portrayed outside of the performative sex acts found in porn.
It's very interesting that despite all of your exposure to gay people that you have this sort of reaction. Why do you think you have this sort of a reaction with two men but not with a man and a woman? Do you think you have any sort of idea?
No different than seeing two fat ugly people showing PDA. Some things I find beautiful. Some things i find infuriating. Some things I find yummy. Some things I find funny. Some things I find gross. There will have to be an avalanche of shit falling off my priority ladder before I make room to spend time figuring out why I find something gross.
I find perspectives like yours interesting because I experienced something similar when I was a closeted bisexual, and working through internalised homophobia was necessary for me. However, I have gay friends who are icked out by heterosexual PDA, and so I don't feel comfortable assuming that what you're experiencing is homophobia without applying a similar lens to what my friends feel (which feels wrong, because as a bisexual, I find both The Gays and The Straights deeply confusing)