I agree. We're only hearing the mother's side. Perhaps his objection was more about the curriculum spending too much time on Talmudic studies, and not enough time preparing the kids for holding a job in the secular world and ensuring the kids can function outside the Chasidic community.
Kernenman’s school is not a Chassidic school, as is mentioned in the column (toward the beginning). You’re also “not just hearing the mother’s side.” The piece was written after going through hundreds of pages of court testimony, seeing a letter from one of the boys and photo evidence. But why let facts get in the way?