One of the reasons why I liked persona 4 is it dealt with issues not brought up much in games, at all. It's easy to see Kanji just as someone coming to grips with homosexuality on the scarcest surface, but come on, nothing else about his link was like that. Shadows are always supposed to be take the most embarrassing aspects of their real selves solely to get them to deny them so they can be free. Like someone else said, that idea gave birth to that form of Kanji's shadow, nothing else.
Same with Naoto really. Though hers wasn't really about being male/female, just being misused because of her age. Because of that, of course she'd want to keep her gender hidden, she's already been somewhat shunned because of her age.
These are real issues, but not what some people want them to be. It's like anything else, interest groups trying to fit a square peg into a round hole. /shrug
And yeah, Yosuke was hatable a few times during the game, and the camping scene is definitely one of those times. Hell, the swimming scene after didn't exactly endear his character either. If anything, his sole purpose on the game(besides being the mouthpiece of the investigation since we have a silent protagonist) is comedy relief, so he has to say idiotic things so you can laugh at him when someone happens to him. Way I've always looked at it anyway. He's a bro, that starts off as a major idiot, then gets better over time.