First off, their baffled and barely suppressed rage when confronted with the fact that art, cinema, popular culture, technology, history, geography and social norms didn't obligingly come to a dead stop when they were given their teaching degrees tells us that we're dealing with pissants who don't want things to change so that they can still know everything.
The secondary qualification is a total lack of sympathy for their charges because the Luanns of the world don't see the point of learning obsolete knowledge from a droning fool who has made a pagan idol of whatever mush was pounded into him at Teacher's College. To a Fogarty, not knowing the grab-bag of factoids he mistakes for the wisdom of the ages must mean not that he's an imbecile stereotype puking forth bullcrap he's too gullible and timid to question but that the no-good kids don't know what's good for them.
The end result is that we're dealing with two tweedy throwbacks instilling a hatred of learning because they don't know anything useful and hate the children who remind them of that. Given that Liz is the same sort of mushhead and has the same lack of sympathy for people who get in her way and question her alleged knowledge of the world, she's walking down the same ruinous path to irrelevance and failure as a teacher. This means that she's more than capable of thundering on about how children must be lying when they say that they didn't mean to do wrong.
The sad thing is that unlike doctors and dentists, we cannot sue teachers for malpractice. Were tenure to be overridden by legal action, the Fogarties and Phelpses and Lizardbreaths of the world would be denied the chance to witlessly and smugly snuff out the light of knowledge and possibly be given a new better role when they were processed into animal feed.