I can't speak for everyone, but my son's self esteem was worse undiagnosed than diagnosed. He felt stupid that he just couldn't get the stuff everyone else was getting, especially things like managing conversations, switching gears and not being able to get his mind off certain topics and actions. He knew without a diagnoses that the other kids seemed OK when the teacher changed the book she was planning to read or the favorite oatmeal flavor ran out or they left one minute later than usual. He knew other people seemed to have friends. A diagnoses actually gave him something to work with, and an idea of having corresponding strengths with his weaknesses.
As someone who grew up with a social disability that I guess falls under "other" (NVLD) I don't think that social skills classes with people on the spectrum in the group would cause any difficulty and while I just looked at that new DSM V proposal and I'd have to say that I'd probably barely fall short on the obsessive component (I do have OCD but it's not quite the same type of obsessive, as in that I don't enjoy it like my son), if I had been misdiagnosed it would probably have done less harm than the lack of treatment I grew up with. I guess there's the odd person misdiagnosed (take a look at the similarities between some of these disorders) but most are probably accurately diagnosed and it's not like you catch autism, from being in the same social skills group (I kind of felt like the article said that).
Also, I think the author was a ninny for focusing so much on verbal difficulties. I think it's way easier to get a false diagnoses focusing on difficulty with verbal communication rather than social impairment as everything from hearing impairment, to auditory processing to trouble getting your mouth around words affects whether you speak late. My late speaking youngest son (no sentences till three, made up words, started primary with 2.5yo level speech) would seem more at risk by that criteria but my early talking oldest really firmly falls in the spectrum socially and in terms of obsessiveness. Now that my youngest child's words have caught up, he can function socially and academically and in sports with so much more ease than my ASD son.