I understand what you're saying about being careful with labeling, but I would like to note that what wasn't mentioned in the article is what defines autism or Asperger's. Shy, introverted, easily overwhelmed, and quirky are results of the things that cause Asperger's not what makes the definition themselves. Some of the things that define Asperger's is that they literally sense the world differently. Their senses work differently. Noises are louder, they can hear pitches most people can't, lights are brighter (louder, too, if you will), they sometimes see as if the world were a badly tuned rabbit-ear TV, they are often super-tasters, they feel things more...well just more. A girl with Asperger's told me once, "I'd rather be punched than tickled." Other things are that they can't read expressions and nuances very well. Because of this they often struggle to express themselves. I can only imagine this would cause a lot of the symptoms in and of itself. I'd be introverted, shy, and easily overwhelmed too. Frustration can very much lead to very dark things. But honestly, the world is full of every kind of frustration and anyone can reach their limit.
I understand the point that Asperger's often means more than just shyness and being easily overwhelmed. However, the spectrum is a behavioral assessment, and application of the label varies. We can label two people as having Aspergers, but cannot say whether or not they have the same physiological condition, and yet we just established a rationale to prescribe medicine as if they do. IMO we often put too much weight behind definitions, and treat problems as if they were well-understood when they are not. Psychiatry is an imperfect science and practice, and I think it should be very honest about that. For those that would be put on the less-severe part of this spectrum, I think it's debatable whether they benefit from the label or not. A lot comes with that label, some of it may be helpful, and some of it may not.