Math teachers, as a population, are abject failures. Every school day they do incalculable harm to the wellbeing of our society by taking everything in the fundamentals of instruction and doing the exact opposite. They not only fail to cause students to develop a functional understanding of the subject, they instill a pride in their students of that ignorance.
College math professors are no better and possibly worse. We call them "professors" because "teacher" is an incorrect descriptor. Very little teaching goes on in college classrooms.