From what I've heard of hardcore and hardcore punk, I think I agree with what you've said, and I believe that you provide some very interesting psychological insights into the target audience.

But if we take "young" out of the equation, it would seem that most "extreme forms of rock and metal" are target to a male audience (whether intentionally or not) of whatever age.

Looking at my favorite genre (progressive rock), the most ardent fans tend to be male (though often somewhat older than the audience of hardcore punk). This isn't to say that women can't like hardcore punk or prog (many do), but that the most vociferous fans tend to be men. What that says (assuming my generalization is perhaps valid), who knows?