Matt Yglesias figures that, since he’s able to cut his own hair, it’s silly to license barbers.
His commenters point out to him, fairly rudely, that people who handle straight razors probably ought to have some training and prospect of inspection from the authorities for health reasons. And that beauticians, who handle dyes and other chemicals, really need to be regulated. Apparently, they’ve explained this to him once or twice before, and hence their irritation.
Mostly, I think the commenters are right. While the free market would probably regulate simple barber shops — as opposed to beauty shops — with reasonable efficiency, we’d hate to have barbers routinely cutting people with infected implements. Let’s just say that the signaling mechanisms for that sort of thing are too slow for comfort.
Further, in terms of arguing by analogy, if Matt is an unlicensed barber, I’m an unlicensed taxi driver and restaurateur. The idea that because people can be trusted to do something for themselves, they should therefore be allowed to do the same things for the public on a professional basis is rather thin.