...create a generation of teenagers who think metal is about crystal meth, dressing like rappers, jumping up and down on ther spot and making "bling"...
I sincerely doubt that this actually happens.
And just out of curiosity, if metal is
ours, define
us, do we all fit the same mould? Should we? What would I have to do to earn the right to use elements of metal in my music? People's musical tastes run the whole gamut from minimalist drone to baroque, with combinations of this and that and what have you. We sure as hell have different tastes and the music you and I write would reflect that.
If artists are creating the music they want to create, choosing aspects of what you could define as metal and incorporating into their own style, so be it. It isn't hurting anybody, or tarnishing the image of metal as a genre. For example, the whole Limp Bizkit rap-metal phenomenon spawned its own subculture completely. It's got nothing to do with the metal subculture you are a part of, aside from the music sharing some elements.
Music belongs to everybody because ultimately (unless it's solely a commerical profit thing), it's all about self expression. Inter-subculture conflicts of interest are best left to teenagers - adults should focus on music.