As the stepfather to an Asperger's kid, who was diagnosed under the DSM-IV by real, actual doctors, I have a dog in this fight.
Manedwolf is right that there are parents out there who will seize upon the disorder-of-the-month in order to explain away their Precious Little Snowflake's behavior problems, because anything's more palatable than having to swallow the "Oh, and you're a crappy parent" pill.
On the other hand, Asperger's is a real thing, and parents of true Asperger's kids have to deal with a lot. Asperger's is, first of all, a syndrome, that is, a collection of symptoms that tend, as a group, to point toward a specific disorder. For solid diagnosis of AS, a kid has to have a certain number of the common indicator symptoms, and no, they can't all be put down to bad parenting (gross motor skills and coordination are often well below norm, for instance). There is evidence of a correlation between AS and a partial breakdown of the myelin sheathing on the neurons in the brain. Myelin insulates the neurons from one another. Breakdown of myelin means more crosstalk among neurons. More crosstalk means, among other things, a weakened ability to differentiate and categorize stimuli.
Example: A normal person getting ready to cross the road can hear a car coming, and a jet plane up in the sky, and prioritize the car as more important to the immediate situation. AS people sometimes cannot do this, because of the crosstalking, and so they may pay attention to the airplane sound, ignore the car sound, and step out into the road.
Because of the inability to instinctively filter out stimuli, social interaction is a nightmare for AS people; body language, for instance, is a mystery to them, because all stimuli are coequal in their perception, whereas most of us can filter out a person's movements that are non-communicative, any movement that another person makes is registered and paid attention to, and it's not actually possible for the human mind to sort out all of the stimuli we receive.
Lack of social skills leads to awkwardness, and the downward spiral begins.
This teacher's career should be taken out back behind the woodshed, shot, cut up into little bitty pieces, and buried alive. And I stand by that even if the kid isn't Asperger's. Because kids are mean enough to one another without a teacher encouraging it.
-BP