I'm sure that we all know straight couples who are frank about their terrific sex lives. But, while they may show each other affection in public, they don't want to exhibit their most intimate sex acts to all comers.
Why should male couples who happen to be sexual partners in their private life desire to show all their deepest acts of making love to the general public, even a paying public. This can also apply to groups of guys who like to have sex with each other but don't necessarily put it all out there, sometimes for professional reasons. It doesn't make them straight. I think of someone like Billy Essex, who long just acted like a jerk in videos because that's what sold on Trigafilms, but now has great sex on video with guys like Louis Jacks who he says have been his "mates" all along. People evolve. (Look at Paddy O'Brian's slow development. That doesn't mean that he necessarily used to be dishonest with us when he wouldn't suck a cock on camera.)