Reductionism: Liberals like to reduce the number of those who object to the ed system to one ("oh, it's just those religious nuts") --which they label as homogenous and treat as one entity. You could have a rich diversity of religious & general community-based folks complaining about something, and liberals will reduce that chorus of voices to "an individual's sense of propriety" motivated by the same religious spring.
The fact remains that ONE anonymous letter (lacking the courage borne of convictions people send anonymous letters to complain about things) is all the complaints that the article mentions.