I think we need to be careful about over-using the terminology of terrorism, cheapening it in precisely the way some conservative Christians have cheapened the term “persecution,” using it for cases in which someone merely disagrees with them, or even for cases in which all that happened was the loss of their ability to persecute others.
Jesus taught us how to evaluate such cases. Put yourself in the other person’s situation and see how you would feel. If someone were to teach in a class that Christianity is wrong, how would you find that?
If the teacher who says this sort of thing is a Christian, they ought to already know not to say such things.
But even if they are not Christians, they should be able to understand why, in a pluralistic society, it is inappropriate for children to have their own identity, or that of their family, denigrated by someone whom they most likely respect and view as an authority figure.