"judgmental attitudes, fear of being cold-shouldered because you don't play the 'right' stuff, and unwillingness to risk getting embroiled in the kind of fight we've seen here, certainly doesn't encourage joiners"

You really haevn't heard a "discussion" between the adherents of indie, metal (several subsets), emo, and screamo, have you? And if you add the various sorts of Mobo into the mix, beware of an explosion!