“Tolerance” is a feel-good buzzword in our society, but I fear people have forgotten what it means. Many folks are proud of their “tolerance” for gays, working women, Tibetan monks in cute orange outfits, or blacks sitting at the front of the bus. But what they really mean is that they consider such things to be completely appropriate parts of their society, and are not bothered by them in the slightest. That, however, isn’t “tolerance.”
“Tolerance” is where you tolerate things that actually bother you.
Robin Hanson is correct that few people are truly tolerant but peculiarly for Robin he calls for more true-tolerance anyway. I'm all for more tolerance but Robin's own examples suggests that social change is not much driven by changes in tolerance.
As I suspect Robin would acknowledge, gay rights have not advanced because of more tolerance per se, i.e. they have not advanced because more people are willing to accept behavior that bothers them. Advance has occurred because fewer people are bothered by the behavior. Note, for example, that if the former were the case we would not see more gays and lesbians on television, as we do today.
When we are required to confront things that bother us we sometimes (often?) reduce
cognitive dissonance by changing our preferences so that we are no longer
bothered. Thus libertarians and other true-tolerants may play a role in encouraging the intolerable to come forward, thereby forcing the intolerant to reduce cognitive dissonance by accepting what was formerly intolerable. In this sense, a few more true-tolerants might help to tip society towards acceptance of some variant practices.
But since few people are or ever-will-be truly-tolerant, tolerance by itself probably can't get us very far towards a society of peaceful variation. Instead, we will have to argue that variant practices are normal, not bothersome or a subject of indifference. The route to drug legalization, for example, is to encourage more normal people who "smoke pot and like it" to come out of the closet. Kudos to you, Will Wilkinson! In the case of marijuana, I think this is possible but for many of the present and future variant practices mentioned by Robin, the limitations of tolerance put a big constraint on those that will ever be "tolerated."