If I was forced to admit that sometimes markets were bad, then I'd have to re-evaluate our entire economic system - what if healthcare markets, gun markets, even employment markets were up for debate? Under what criteria would one even evaluate those? Moreover, how could we even tell if they were genuinely bad or good, or if the particular cultural context and social indoctrination predisposed me to
think they were good through social conditioning?
Why, for example, would a market for health care be good, but a market for child-imprisonment be bad? If a market for child-imprisonment were susceptible to bad actors, perverse incentives, and bad outcomes, then it stands to reason the same could be said of all markets. That's a rather large implication, I'm sure we agree on.
If humane child imprisonment is valued by the market participants, then that's what the market will provide. If a market doesn't signal that it's important, then it's definitionally not important. That's what price signalling is all about.