That you would even consider that the teacher's reaction might be appropriate is all anyone would need to insist that you never be granted access to children in any capacity.
The children I've been around have been raised properly. I know their parents personally.
You can dispense with the assumptions.
Then again, what would have been the appropriate reaction by the teacher? Tell us.
Would you have the kid removed from the classroom by the resource officer? Sure, that would resolve the issue for the day. But the next morning...
Suspend the kid? That solves the problem for a minimum of two weeks to a month. And then the child is placed directly back into that environment, having learned nothing in the process.
I mean, temporary punishments are temporary. The lessons they teach are temporary. Physical reinforcement, like a spanking (or whatever that teacher did with the stick) teaches a permanent lesson.