GRE Problem

I find it strange that it is Education majors who consistently score the lowest on the GRE test. From my reasoning, it is Education majors who educate our children, decide how they should be educated, and probably are the same ones who make up these exams and exam questions. However, by their own assessment or by the assessment, educators are the "dumbest" out of every group. They have failed according to these exams so why are they allowed to educate other people? Why are these assessment tests the standard for our society and education when educators themselves fail on these tests?