Certainly, not all teachers are like that...DS has had two who are emphatically not, bless their souls. But it's interesting, and a little scary, to see behind the curtain.
Honestly, before I had a child who could read this well this young (DS read the Narnia series at 4, for instance) I probably would have been skeptical that children like this existed. I read at 4, too--but not Narnia. But the thing that bothers me is that teachers ought to be open to the idea of difference, right? You ought to go in there with an open mind (you may be allowed to be skeptical, a bit) and see what the child can do. You can't just be so damned reactionary.