If criticism is valuable why not be more critical?

Subjecting anyone of any age to coercive education (unwanted criticism) is not taking them seriously. Nor is it even taking the valuableness of criticism seriously! Let alone taking the growth of knowledge seriously.

Surely criticism is always good?

he idea that criticism of others is always good is a mistake, just like it is a mistake to think that education is always good. It may be good if it is wanted, but not if it is unwanted. Coercive education is not and never has been Taking Children Seriously.