So, you're suggesting that men watching porn where one woman takes multiple dicks are gay, while the most hetero porn they should be watching is lesbian scenes?
Doesn't work that way. Porn is made by men mostly, for other men mostly. And mostly depicts heterosexual sex, mostly featuring one, or more woman having sex with a larger number of men. It's not a weird coincidence though. It's in the name. 'Porne' means a whore in Greek. And a whore is basically a woman who has sex with multiple partners. Pornography is reading or watching whores doing what whores do.