Yes, I think that's sensible too. What about certain ideological material, for example religious extremism or Nazism that advocates genocide of other ethnic groups?
Not something that children should hear about in schools other than teaching the history of who the Nazis were and the horrible crimes they committed. I don't think grade school kids need to hear about things like that. That should wait for an appropriate age. Like many other things. That should be common sense to any normal/reasonable adult.
Teachers should definitely not be advocating for Nazism, communism, socialism or any other belief system. That is not their job.
Adults should be able to voice their opinions to other adults even when we hate what they are saying unless they are advocating for violence against innocent people.
I think there should always be free and open debate when opinions differ. Get all the evidence out in the open. Trying to cut off debate or hide evidence is something people do when they know they are wrong and their opinions or arguments can't stand the light of day. Get all the evidence out in the open and see what is true and what isn't.
If your set of "facts" are true, it should be easy to defend them and you should welcome the debate instead of trying to silence people who disagree.
*not referring to you or anyone else here personally when I use the words "you" and "your".
The problem with "religious extremism" is with who is doing the defining. As long as a religion is not advocating for killing or harming others, they should not be censored, no matter how crazy or silly their beliefs may seem to me. I could be wrong. The people who believe in "The Flying Spaghetti Monster" may turn out to have been right.