"Good" means objective and unbiased. The right wing always rail against political education, their dishonest take being that teachers of such will be reds under the bed, the more honest but never stated take being that a politically-educated electorate would be less likely to vote Tory. As I've said before, it's perfectly possible to teach an objective and unbiased curriculum in such areas as politics and religious studies. Teachers routinely keep their own predilections under wraps in the classroom. What you seem to imply is that the only good teacher is a Tory teacher. Do correct me if I'm wrong.