the metalheads we've come across are the sweetest, loveliest, gentlest people ever... the music is a great outlet for young people, the moshpit seems to be a great place to vent and let off steam, and i think the music must be cathartic or something... on a personal level, it's been great for my kids - they listen to (and play) the loudest screamiest intense stuff, but they're both such level-headed, very grounded, gentle and caring kids, and pretty quiet and shy (apart from when they're performing), and brutally serious about their music - they push themselves really hard - brutal perfectionists... but they get so much out of it...
the metal scene is also changing, moving away from drink, drugs etc. and there is now the "straight edge" thing going on, where many of the musicians my kids are meeting are health fanatics, vegans, and don't drink, smoke or take drugs and really look after their bodies, which i think is awesome...
metal offers an amazing community for young people, but they have to go looking for it...
on a more general level, i think young people need to have a physically challenging outlet to let off steam and clear their heads and get them "out of themselves", whether that be music, sport, or performance arts like dance or circus, or even competitive equestrian sports... a lot of kids i've come across that are heavily engaged with these kinds of activities are often really well adjusted - kids need something to focus on, to carry them thru turbulent teenage years, rather than drifting aimlessly...