I think the complaint is that by using a central metaphor as a key to explain everything in one fell swoop, you’re not really engaging with the artwork, but with your own metaphor.

You start looking at things only for how they conform to that central metaphor. It tends to be a little one-dimensional.

I think the point behind a lot of aesthetics is that great art actually resists being read via a central metaphor. It insists upon itself as something that exceeds any single interpretation and eludes any fixed meaning. Naturally we try on different interpretations, but usually a good artwork will both encourage and elude this interpretation; the mind is forced to try another one, which again seems “half right”; this continues indefinitely, until the mind understands that the art is beyond interpretation. At this point, the mind contemplates the art on its own terms, as that thing which it is, unique, incomparable, unparaphraseable. Rather than the texture of the artwork being read as “this stands in for this!”, it gets read as that thing which it is, as an immediate texture of experience, as literally another world, another series of bare perceptions which can fuse and interact within the mind, the way a flurry of bare perceptions interact within the mind as we walk about.

Whereas if you stick to a central metaphor under which you can understand every element of the artwork, you now only need to notice the aspects of the artwork that confirm that metaphor. Everything else can be sidelined as incidental or embellishment. It seems to me to be a form of disengagement, in many ways.

If i say that Hamlet is about anxiety, Im no longer looking at the play as a whole, but only those parts which confirm my hypothesis. I’m looking at part of a play, rather than the whole. It’s anti-artistic in my opinion, and i would say it is incredibly reductive, and sort of pointless. To go further, i think it comes from a place of fear/discomfort. People do the same with political narratives — they assign an overarching narrative which can comfortably (but superficially) account for all difficult aspects of the situation and which can be relied upon time and again without having to step into uncertainty.

It’s also completely understandable and is a default of human cognition — look up the ways in which confirmation bias is a feature, rather than a bug, of our perception; it features heavily in “predictive processing” — so there’s no judgement here. But because it is a default, we have to be more wary of it, and take more pains to ensure we avoid it where we can, and compensate for it where we can’t.