Probably because they are elected by the community and he has no real jurisdiction, other than getting attorneys to take it on.
Picked by the community? I doubt it. As a practical matter they are selected by the teachers union and run as a slate with union money and manpower behind their campaigns. Few people vote and the parents and town get pretty much what they deserve. Then one day they wake up to what is going on but they are stuck at least until the next election. These people will not resign. They will not be prosecuted, and they may well win the next election unless the teachers’ uniom decides to replace them with some equally bad picks.