That was such a bizarre reaction that I was totally taken aback. I mean, it's not like I'm offended when someone mentions bad accountants or writers. Obviously there are people of different abilities in any job. Some are good, some are bad.
And in fact, pretty much everyone has had experience with good teachers and bad teachers. I sure did when I was in school.
So why was she denying reality and insisting they're no such thing as a bad teacher? Of course the obvious conclusion is that she was one, but since I've never seen her in a classroom and know very little about her I don't think it would fair of me to accuse her of that. Still, it's easy to see why schools keep getting worse and reforms keep failing, when the biggest interest group related to education vehemently insists that no problem could possibly be the fault of any teacher ever.
I don't claim to be an expert on the educational system. But based on my experience having gone through it and being generally observant, I'd say there are three kinds of teachers in the world:
1. People who are teachers because they like teaching.
2. People who are teachers because they needed a job, and couldn't figure out what else to do.
3. People who are teachers because they believe they ought to do it and it's a noble profession. Then once they actually try it, they hate it. But instead of sensibly saying "I guess I'll look for a different job that doesn't make me miserable," they feel guilty over the fact that they are miserable doing something they think is morally noble. So they stay in the job that they hate, and that turns to resentment, which they take out on their students.
Think back about all the bad teachers you've had in your life, and I think you'll easily recognize how they fit into either category 2 or 3. They either don't care, or they actively hate their students. Whereas the good teachers you've had fit into category 1, and are happy teaching.
I think any school reform that's going to work has to be based on setting up hiring practices and incentives so we end up with more good teachers in category 1, and less bad teachers in categories 2 and 3.
But as long as teachers unions deny that bad teachers could exist, that's not going to happen.