The whole idea of a bunch of people sitting round and singing songs out of individual copies of the same book does seem pretty strange, outside the context of a church service, and I don't think it's found it in many cultures.

But perhaps it should be recognised as yet another expression of a type of activity that is characteristic of the particular culture in which it has emerged. Maybe it reflects the fact that Americans may tend to come from a more diverse set of backgrounds than people in other places, and from less settled communities, and that sitting in church and singing from hymn books is a much more familiar activity for them anyway.

In other words, this blue book stuff is a kind of tradition of its own, and deserves the same kind of tolerance we extend towards other traditions that can seem a bit ridiculous to outsiders. For example Morris Dancing.