Trust me, I have seen my share as well, and I am willing to bet a buffalo nickel that the majority of them are NOT education majors...
There are morons in every career field. The teaching profession simply seems to bear the bulk of the scrutiny here on FR because probably 75% or more of FR's denizens believe that ALL teachers are liberal, lazy, and ignorant. It gets tiring listening to the same old record play over and over again...
If you are tired, take a rest. This is still a free country and no one here one Free Republic is holding a gun to your head.
I can think of dozens of professions that are so academically rigorous that being stupid, or lazy would preclude finishing the program. Also, being stupid or lazy would immediately eliminate these people from the job market. In a FREE market the lazy, stupid, incompetent, and ignorant are fired! That's what a free market does.
Government schools are government created price-fixed monopolies under the thumb of one of the world's most powerful unions. (That is a prescription for maintaining permanent life support for the terminally brain dead!) Firing a government teacher, nearly requires and Act of Congress, and their rate of dismissal proves this. In New York City they even have a term for the places where they warehouse the incompetents: “Rubber Rooms”!
Ignorance, laziness, and stupidity are far less likely to be maintained in the free market professions, and far more likely to be found in the union protected, price-fixed, monopoly government schools.
Finally, only teachers are responsible for their collective SAT, ACT, and GRE averages. If you find a bright teacher ( and I have), some kid somewhere is stuck with a dumb one. That's what “average” means!