Any teacher who is certified (hopefully in that subject) may teach an AP class.

Sometimes, a teacher teaches an AP class by seniority, no other teacher wants it, or through rotation.

As a former AP History teacher I am sorry to hear that your experiences with at least some of you AP teachers have not been satisfactory. You may have the same experience in college. An AP teacher needs a great deal of time to prepare for classes. That time is usually not given. College teachers usually have a great deal of time to prepare and frequently better facilities particularly in the sciences and in libraries. It is more likely too that AP classes have students who are not interested or do not have an aptitude for that subject.

I am sorry for your bad experiences but ask yourself were you better off because you took these classes.