Chinuch is not Tochacha. If it is, then the parents need a parenting class. Chinuch comes from both parents and a unified message must come from both parents (as well as all other partners in chinuch, yeshiva, school, shul rav etc). If father demands his daughter dress according to most stringent opinions and her mother does not, forget it.
I better read the article before I put words in the mouth of Rabbi Kelman, but I suspect he laments that fathers and husband are absent altogether, meaning no direction at all comes from the home in this matter, making the schools out to be the crazy machmirim and the home practically a free for all.
Would anyone disagree with the thrust of the message if we substitute kashrus for tznius as the subject for his article?