I think it’s a load of crap. To be more specific, there’s no evidence that anything can change your sexual orientation. Besides exposing you to more sexual activities, I certainly don’t think porn has the power to “turn” someone gay (which is the implication). Plus, from what I’ve heard of the forum/idea you mentioned, it sounds pretty unhealthy. Masturbation is natural and so is being gay. I get how exercising self control can make you feel empowered but you have to make sure you’re spending your energy in the right place. Anything that suggests miracle cures for all your problems deserves skepticism, in my book.
No, your sexual orientation doesn't change from watching porn or from masturbating. Your relationship to sex, the way you view sex, your expectations from a sexual encounter may change(unhealthily so) much the same way your expectations about anything can be shaped by what you're exposed to, but your sexuality can't change. What can, at most, happen, is make you realise something about your sexuality you weren't aware was there but was always in fact there, even if dormant.
I think it’s usually the other way around. (Sexual Orientation is already there, which could influence what porn you like)
No, it doesn't change your orientation, otherwise, we would have pretty solid research about "converting" people to different orientations, as it would be a simple process - simply expose them to porn. However, it doesn't work that way. As @Spartan 117 pointed out, be careful with these "no masturbation" forums. Yes, some people struggle with addiction to porn and masturbation, but most of these forums/content don't solve the situation - instead preaching the extreme opposite, which is also unhealthy. If you are struggling with a sexual related issue, a therapist is a much better and reliable choice.
