> I also don't buy that groups don't make better decisions than individuals.

I didn't say that. My example of the market includes companies that are groups of people.

> We know that diversity of thought and opinion is one way to make better decisions in groups compared to individuals; why would there be harm in believing that consensus building, debates, adversarial processes, due process, and systems of appeal lead to worse outcomes in decision making?

I can see this about myself. I don't need to use hypotheticals. Time ago, I voted for a referendum that made nuclear power impossible to build in my country. I voted just like the majority. Years later, I became passionate about economics, and only then did I realise my mistake.

It's not that I was stupid, and there were many, many debates, but I didn't put the effort into researching on my own.

The feedback in a democracy is very weak, especially because cause and effect are very hard to discern in a complex system.

Also, consensus is not enough. In various countries, there is often consensus about some Deity existing. Yet large groups of people worldwide believe in incompatible Deities. So there must be entire countries where the consensus about their Deity is wrong. If the consensus is wrong, it's even harder to get to the reality of things if there is no incentive to do that.

I think, if people get this, democracy might still be good enough to self-limit itself.