Do Autistic children misbehave? Of course they do! Are they capable of following rules? Yep! Do they know right from wrong? Sure they do!
But there is so much involved! So much people wouldn't understand unless they work directly with Autism or they have a child who is Autistic.
On the outside people may see certain circumstances as cases of misbehaving. The perfect example of this is the recent story of the little girl and her cheeseburger. It may look like she is being picky. But what others don't know looking in from the outside is the feelings she is having seeing a cheeseburger cut in half for the very first time in her life.
You see change can actually be scary. That cheeseburger was scary. Sounds like she did a good job of keeping her cool! To others she may have sounded like a brat when she said it was " broken " and didn't want to eat it.
Her reaction had nothing to do with behavioral issues. So I say if you haven't any background in this area you are in no position to pass judgement.