There's a particular kind of futility associated with the teaching of philosophy in a formal school setting. It is very common for students to reject and rebel against the very idea of philosophy, for two different and conflicting reasons (which are often, however, expressed simultaneously if incoherently by the same persons).
First, philosophy is dismissed as irrelevant, insignificant, and of no practical concern or value, because its questions of meaning, value, and being are not directly related to any career path or any area of scientific or mathematical expertise.
Second, philosophy is rejected with great emotional vehemence, precisely because many of the questions it raises touch upon people's deepest convictions about morality, politics, and religion, which they identify with, stake their self-worth on, and cling to passionately, like a dog clinging to its favorite bone.
In other words, to the extent that students are not already passionately attached to beliefs relating to philosophical questions, it is dismissed as worthless and irrelevant. To the extent that students are already passionately attached to beliefs relating to philosophical questions, their mind rebels against the very thought of addressing such questions using the method of rational inquiry. Either reaction is destructive to philosophical discussion, and poisons the atmosphere in the classroom.
Teaching philosophy is 90% or more about emotion management, and 10% or less about conveying information and stimulating discussion about philosophical concepts, theories, and arguments. It can be a draining, exhausting enterprise, in particular for those who are neither adept at nor passionately interested in managing the emotions of others.