Parent was observing that the Catholic Church was an exception to GP's point that the written word stiffened and froze monotheistic religious practice, as it blended oral and written transmission.

I was observing that the modern Catholic Church (post-printed word) has offified in exactly that way, with the printed word allow direct dissemination of the "agreed" canon (i.e. pope / hierarchy) to the entire church, thereby unifying them into a single practice.

In counterpoint I offered the number of papal crises and schisms that abounded during the medieval and pre-medieval period (i.e. before printed material became cheap and available).

Ergo, the use of the printed word allowed the Catholic Church to unify and standardize in a way it had not before -- GP's point.

It's indicative that the majority of monotheistic religious splits within Catholicism happened before the printing press, when intervening human parties could reinterprete the canon as it flowed through them.

For political-national-religious entity, the Catholic Church / Holy Roman Empire partnership allowed the Church to become a nation in all but land, by the power its blessing conveyed upon a chosen leader.

https://en.m.wikipedia.org/wiki/Canon_law#Catholic_Church