These guys founded in 1925, so most of the adults would have gone to school at a church or otherwise had a religious education, because that was the main form of education in pre-revolution Soviet countries. It was incredibly common for young women to be sent off to a seminary to become a nun instead of learning math or history.

I try to bring this up when defending the USSR's policies regarding religion, or at least I hope to put this into context for more people. Religion in tsarist Russia wasn't simply some affiliation people had or a feeling in their heart. It wasn't simply reading the Bible before dinner with your family. It was an entire structure of bureaucracy onto itself.

In a typical peasant village, the local priest could be the school teacher, the village accountant, he could organize local events, he could be a local government representative. The church was sometimes the only media the peasants consumed, the priest was the one to tell you about national events or news. Priests and clergy had a functional, structural role in maintaining society. Disentangling the church from matters of everyday life became a serious concern for the socialists, as it should have been.

I know it sounds goofy now to consider what a "militant atheist" is, but that's because we never experienced the feeling of seeing someone's daughter dragged away to become a nun, or a village of peasants kept illiterate on purpose.