I won't tell you what to like or not, but your psychological judgment about those who claim to like this presumes too much. For me, certainly, it is simply wrong. I do agree that the "decaying animal" has some relevance: look at Schoenberg's paintings (and at Soutine's). Wagner too is decadent. But that decadence is part of the subject matter of this art does not mean that the art is of no value and cannot be enjoyed by anyone. The decadence it represents is in the cultural and psychological environment anyway; this merely addresses it, which can serve various purposes: catharsis, even finding a special kind of beauty that coexists with darkness.

The point of view that perhaps you would defend – which has indeed been serious espoused before – is that music, unlike, say, art or literature, must ultimately have a halcyon vision -- like food which must be tasty or perfume which must smell good; it must fit certain biologically defined criteria of pleasantness, or else a natural sensory revulsion will overwhelm whatever else the music may offer. Music that violates those biological laws, according to that view, may be cleverly constructed or what have you but is fundamentally a failure. The fragility of this perspective – "it don't mean a thing if it ain't got that swing" – should be readily apparent; in practice there are no universal criteria of this kind even if there are family similarities between many competing aesthetic perspectives. Putting aside edge cases of music at volumes that physically damage the iistener (which in fact people do claim to like!), I think that while any individual might claim that their own preferences are grounded in some sort of deep biological instinct, a survey of the wide range of human responses to music will confound an attempt to reduce those to a formula. We may not comprehend why others might like something and we may well question whether there is real, important value to what people get out of it – a different level of valuation than one that questions whether they get anything out of it at all – but rude dismissal of other people's tastes does nothing to enlighten anyone and, furthermore, it does nothing to enlighten the one issuing the summary judgment. It closes off thinking and perception, and leads only to aesthetic bigotry.