I always assumed that in pre-MG SC era there was a 50/50 split between bisexual guys and heterosexual guys with few gay guys from time to time.
The bisexual ones enjoyed the sex, had no problem staying hard and obviously produced better content. But they almost always dated women( like most bisexuls lol) so ignorant people assumed they are str8 and it was just "great acting".
The straight ones are those where all those horror stories about being able to stay hard for 30 secs, constant need to look at lesbian porn, several hours of repeating, faking cumshots etc.
I have no doubt bisexuals were pissed off when they wanted to have a good fuck with a guy and he couldnt stay hard, acted like he was rÂŞped and didnt wanted to kiss.