What if the child was being overly disruptive? What if the child was doing something terribly vial and disgusting on a consistant basis?

The teacher can't lay hands on the kid, the other kids can't either, it's interrupting the learning of our future. While it was wrong to single the kid out in front of the class, the kid should have probably been removed and put somewhere else, because it's wrong to sacrifice the good of the many for just the few.

Just as it's wrong to punish a class of kids by no one going on a field trip for one asshole kid killing the class pet.