The young people talk and explain in one understandable language for them, and the teachers are basically always much older than them and unich slightly different worldview. Accordingly, students are much easier and more pleasant to communicate with the same as they and develop together. Teachers with students have different goals and views on life, so they can not always fully explain something to each other.
Your opinion is very right. We can easily learn from friends, but the ones who make us more knowledgeable are the ones who are ahead of us - the teacher.