We find it difficult to trust taste. We want some concrete system, some grid, a set of rules we can all agree to, can come to a consensus on. Taste, by its very arbitrariness, appalls us. What's worse, there's no arguing with it. We can't convince anyone he really likes peas if he throws up at the sight of them.
Taste is too personal.
It forces us to depend on ourselves when we would rather depend on morality.