Earlier quoted context omitted.
I know a few people like this and can confirm: they're extremely difficult to be around and take pride in it, feeling great about being "free thinkers" and breaking from the "herd mentality". This I feel is unfortunately counter to the design of humankind, where we are—as you said—social animals and the only way to change for the better—at a species level—is to change together.
Isn't that basis for criticism a little broad? It sounds like you're saying that vegetarianism, every religion, and a higher than average scrupulousness towards not littering are in the same category as picking your nose during a one on one.
I'm talking about "open handed" issues where people tend to debate and negotiate: preferences, not convictions—if 3/4 friends want to go get a sandwich, but 1/4 insists on either salad or "go without me", this can be taxing on the relationship—especially if they also are usually open to sandwiches and have no strong conviction against it.