The Parkers have no legal standing if they remove their son. The court here would tell them, your son no longer goes to the school, case closed. For the time being, they feel the school system needs to be reformed, legally if necessary, and they are unwilling to just leave it as is, for the sake of the rest of the children.
Again, SOMEONE must care enough not to just run, and I am sure they speak with their son often about the right morals and values, and what not to say in school.