The difficulty the telepaths have in learning with Michael is that they know more than they should, and people would wonder why.
Michael is one of the few people in the community with an education, because his parents were not satisfied with the “sketchy” farm education. He is sent to a more advanced society in Kentak.
There, he began to learn a lot of things our old ladies had never thought of. It was natural for him to want the rest of us to know about them, too. (ch 8)
Michael wants the other telepaths—the children who can talk to each other in “thought-shapes”—to learn from him so they can protect themselves from the backward paranoia of their community. If they are found out to be deviant, they will be expelled or killed.
When Michael is in school, he can communicate what he is learning with the other telepaths. As a result, they learn what he learns.
[He] was able to hand on to the rest of us pretty nearly everything he was being taught -- even some of the things he did not understand properly himself became clearer when we all thought about them… (ch 8)
As a result, the telepaths become the most educated people in the community. Their ability to help each other and share communal thoughts gives them greater intelligence. Therein lies the problem.
Quite quickly it became difficult always to remember how much one was supposed to know. (ch 8)
The children have to be careful not to give away what they know. They have to do things as they have always done them, even though they know a better way.
The situation of the telepaths is foreshadowing of the larger issue facing society. Their community is stuck in the past, but they are more advanced. Their community holds them back and this advancement is a danger, but in the end they are rescued by a more advanced society—Sealand.
Them David didn't go to school and they're not suppose to no more then ther parents so they had to keep it down on how much they knew.