I've never read "The Wisdom of Crowds" so maybe I'm missing some stuff, but from the general statement I think it would be a terrible mistake to take it as mean

I've never read "The Wisdom of Crowds" so maybe I'm missing some stuff, but from the general statement I think it would be a terrible mistake to take it as meaning "commenters are right" or "consensus is right." It's much more subtle than that. Crowds, in certain structures that yield a useful dynamic, produce wisdom. People transacting in a market allocate resources effectively. Gamblers and bookmakers betting on football matches make good odds. Wiki-editors nitpicking away in wiki-world produce an incredible encyclopedia. Open source, etc. There are also lot of examples of crowds being stupid, and structures that yield a stupid dynamic.