As for the "no homo" thing, it originated in online bodybuilding forum culture because the dudebros felt the need to find a way to express their totally heterosexual admiration of each other's bodies, as in, "dude your lats are amazing no homo," or, "your physique is perfectly balanced no homo."
It's borne of toxic masculinity, of course, but it was the only way they could think of to tell a bunch of other men posting mostly-nude photos of their bodies, "I think you're hot, but in the kind of way where I want to be like you and not because I'm struggling with a subconscious desire to be penetrated by you."