on the one hand, music can be purely abstract art, in which case it requires no thematic direction. the best "classical" music, jazz, electronic music and other mostly instrumental forms are simply to be experienced as sound, and there's nothing wrong with experiencing music strictly as a form of escapism, on that level.
on the other hand, music can be a type of propaganda. it can be agit-prop, it can be commentary, it can be satire, etc, but this type of music doesn't need to have characteristics of music to be interesting, as the function of it is strictly as propaganda. this is the value of folk, and derived forms of folk such as punk rock.
i tend to do both, and i tend to listen to both, but i expect either to function properly in their purpose. so, i'll criticize led zeppelin for being shitty artists, because they were - while listening to the much simpler dead kennedys, because their function as propaganda is exceedingly effective. what was labelled "emo" often failed for the same reason that led zeppelin failed, in the sense that it existed in a category error - it had no propagandistic value, and it had no redeeming musical characteristics.
if you're going to exist in a folk genre (which would also include hip-hop, although i don't listen to hip-hop), you should be exceedingly focused on the propagandistic value of your music. conversely, if you want to produce art for the sake of art - for pure listening value - you should realize that you need to transcend the limitations of folk culture, which are just going to make your music boring, if it's intended to be listened to as music. i'm not as ideological as your strictest punks or your most literal socialists on this point - the end point, after the revolution, when we have freedom and anarchy, when we abolish the proletariat, is to engage in art and science. that's why we want communism, in the end - so we can spend less time working and more time existing. but, that means that if your music is intended to be art - and not to be propaganda - then it had better be actually good.
and, as art, emo sucked - it co-opted a form meant as propaganda, and watered it down to the lowest form of artistic expression imaginable.
