Homophobic my ass. It makes straight men doing gay sex in to a kink. Not gay sex in itself.
I disagree with the point about it making it seem like same sex attraction is a choice. It only seems that way to delusional individuals who can't separate porn(fantasy) and real life sexual encounters. Porn is about providing a fantasy. That's it. The measures straight men must take before a gay scene can be quite complex, and even then not everyone is able to break down their mental barriers that is stopping them from doing it.
You are correct about viagra though. There has to be arousal for it to work. However, some guys are able to go somewhere else in their mind while performing. They either think about women or a fantasy that turns them on. During filming, they must often stop recording, go somewhere else and watch straight porn to get back in the "right mood" to continue shooting.
Also, in Philippe's case, he uses dick injections, which make you hard no matter what you do for a period of time, until you poke your penis again with a needle to release the erection. It's quite rare that he cums in gay scenes. This is why. He feels no pleasure what so ever. It's all an act.
Takes work away from gay men you say? Well, unless we are talking about a porn studio, gay men are free to sell whatever type of porn video they like on onlyfans. I wouldn't necessarily buy a gay man's sex video, if gay4pay never existed. I would probably just buy solo videos of straight men(which I mostly do already). If someone is deemed unattractive, whatever sexual orientation they have won't make customers buy their videos...