I am self-diagnosed, but I don't tell many people about it, and the most I will say is that I have strong suspicions that I am on the spectrum. Most of the people I have told don't believe me.
I understand the blogger's point of view. AS has become one of the trendy disorders, and people can be quick to diagnose themselves or someone else with it. It used to be ADHD, and still is to some degree. "Oh, my kid can't sit still in class, must have ADHD." Or, "That guy's weird, I think he must have AS or something." On the medical side, these days everyone is gluten intolerant, lactose intolerant, and allergic to nuts. The blogger mentions a common problem with medical students who spend hours reading symptoms of all kinds of illnesses and convince themselves that they have some kind of terminal or disabling disease. It is hard to stay detached and have an unbiased perspective on yourself. The blogger points out that many disorders have a lot of symptoms in common with other diseases, and that some of those symptoms can appear in perfectly healthy people. So someone has a headache and looks up on the Internet what could cause a headache and starts to think they have something serious. For things like AS, it takes a lot of time and a lot of knowledge to rule out other possibilities before a diagnosis can be reached.
That said, I think there is a lot of quackery in the mental health professions. Nearly all of the therapists I have seen over the years have diagnosed me as being depressed and anxious. (Seems that stimming looks like anxiety to a lot of them.) Most of them have pushed me to take antidepressants. I have tried a half dozen of them, with horrible results. They have side effects that just make me miserable. I don't believe I am depressed. I greatly enjoy skiing, bicycling, walking my dog, laughing at funny sitcoms on TV, and eating good healthy food that I prepare myself.
I believe that high-functioning autism makes more sense than any diagnosis the mental health professionals have come up with. It would explain lifelong patterns of feeling (and being seen as) "different," difficulty making and keeping friends, a spotty employment history, disastrous dating, and a tendency to become isolated from other people. But I can't rule out the possibility that my parents just didn't socialize me properly at a young age, I spent too much time watching TV by myself, and I didn't get very good career advice. I did well in school, even though I didn't fit in very well, so everyone assumed I would turn out OK. At 62 years old, I don't know if I could get a medical diagnosis of autism, and I don't know if there would be enough benefit to justify the time and expense to get one.
Whether self-diagnosed or with a medical diagnosis, I agree with the blogger that it is best used to provide a perspective and framework for understanding, rather than an excuse for failure or bad behavior.