I love metal. It's an endlessly ridiculous pantomime that by many metrics I take very seriously indeed. It's a vastly stupid genre of music that I often love for its technicality and intelligence. It's as idiotic and ugly as it is clever and beautiful.
Of course, these contrasts are in some ways cheating because metal is an incredibly diverse realm of musical and cultural expression that only looks homogeneous from the outside. In other words, almost every genre of music or grouping of culture contains stupid and intelligent instances when you look closely. However, there is something about metal specifically in that it seems to revel knowingly and gloriously in its own overblown, silly excess: incredibly talented and proficient musicians acting like drunken idiots and producing heavy, extreme and convention rejecting music. There's often simultaneously a serious and successful attempt at profundity, elegance and cultural relevance, alongside a sincere message that none of that bullshit is necessary, and we should all drink beer, scream (usually terrible) lyrics and get in the pit in order to have a good time.
I missed out on punk when it was first around, and haven't succeeded in any subsequent attempt to enjoy or appreciate it. To me, punk is someone outside the castle hurling obscenity boulders from their noise catapults: it's non-musicians attacking music (and perhaps using that as vehicle for attacking whatever else). My problem is that it's easy to criticise from the outside, and whether or not the criticism is correct or deserved - which here I make no judgement on - I find it boring, irrelevant and ineffective when someone shouts about something they have little understanding of. While I appreciate that this is a cop out, this isn't a discussion of punk's failings (or successes), so I'll say that it is of course a lot more complicated and nuanced than that, but that those are the broad strokes of my feelings about punk.
Now I don't in any way think metal or the "purpose of the metal genre" (as if there is such a thing and as if metal was one properly defined genre) is primarily about examining, providing commentary on or "pushing forward" music in general or any subset thereof, but I do know that part of my fascination with the scene lies in the juxtaposition of intelligent, deep, complex or culturally expressive music with the sort of uncomplicated, energetic attitude and surface level offensiveness that punk has going for it. Many metal bands are full of technically brilliant musicians and/or incredible creative talents, but they've chosen to produce something that's generally angry, offensive, commercially obscure or some combination of the three. Therefore, while the "point of metal" may not be, well, really anything, metal is very well placed to be the spy inside our stretched-metaphorical castle from above: these people - some of them anyway - are actual musicians, so I find their choice to produce this kind of output fascinating and compelling and I think that the best way to "attack music" (or the musical establishment), if we feel the need to do such a thing, is through competent musicians such as these.
Lest this all sound incredibly pretentious, I'll be clear that I don't love metal only for the reason I'm trying vainly to summarise above. For a start, it's possible to appreciate the mix of attitude and musical complexity without examining it more deeply than simply the aesthetic appeal of said juxtaposition. It's not something I would try to justify on an objective level, but I simply enjoy energetic, angry music that is complex and interesting, probably (though who can say) independently from any intellectual examination of the form.
I'm also a sucker for technical, well produced music in general, and enjoy that alongside or even over and above emotional expression within music. Again, I wont try to justify this objectively; it's just my taste, and metal is full of incredibly technically proficient musicians.
Finally, like, y'know, drinking beer and playing air guitar and stuff. 'Nuff said.