I love this discussion.
Someone commented a few chapters ago about "Ennis going out of character" when he told Junior about how it was "good for boys to have a queer bar to go to to meet up with each other" and Junior replying that it was disgusting.
I made a reply on my livejournal explaining what happens when Ennis goes and does something "unEnnislike", like confiding something about the dominance/submission relationship to Dupree. First of all, Ennis automatically seems to trust straight men more. Because he identifies with them. He would not have fallen in love with Ellery if he were fem, and that made him okay for Ennis to imagine having a relationship with. He is sitting in a bar where there is a whole gaggle of fem boys acting fem and this is constantly in his face and causes him to ruminate on the nature of his --- admittedly different --- relationship with Ellery, even though there is a marked top/bottom preference in their relationship as well.
One of the things people find a godsend after reading/seeing BBM was having an outlet for communication of their own secrets once they confronted difficult things about themselves... their homosexuality, their isolation, a hidden relationship. Ennis is walking step by step out of a very long closeted life, and having made some initial steps, he is urgently desperate for confidants, and he cannot trust these "fem boys" (part of his annoyance with them.) The only suitable confidant aside from his lover (one man is not enough, he learned that with Jack - to serve as lover, friend, and confidant) is someone else who he respects as a man, someone straight, someone who isn't a caricature of homosexuality that cannot relate to him. Someone with some intelligence, sensitivity, and more than anything, openness to learn more about what he himself is going through. He knows Dupree is curious, but not in a maudlin or casual way, but in a true desire to know and to be able to relate to both Ennis and Ellery, his friends.
I hope that explains what I am digging for here.