Ancient Greek philosophy was protoscientific and therefore protonaturalistic relative to the alternative, which was folklore and ecstatic cults and therapies (as in the Mystery Religions). All philosophy is relatively naturalistic in that sense in that the discourse is rational rather than dogmatic and faith-based. Descartes' philosophy was incompletely naturalistic. He naturalized everything but the capacity for thought.

"Naturalism" is a loose term, or at least there are numerous definitions. There's metaphysical and then there's methodological naturalism, for example. You can look at the content or at the method.

Quine was a positivist, not just a naturalist. Positivism turned out to be an ironic act of religious faith and prejudice, so it wasn't methodologically naturalistic (much as neoclassical economists pretend to be scientific to disguise their political role as propagandists for secular forms of mass exploitation).

Obviously, the Church used Latin to exploit most Christians' ignorance and to maintain the Church's mystique. The Latin-speaking priests were mystagogues who were hiding the problems with the New Testament, which came to light later with Protestantism and the historical-critical method.

But this obfuscation was still a case of dumbing things down for the masses, because the only information conveyed by Latin was that the masses were ignorant and the Church had magic powers and an august connection to Jesus. The actual theological contents were conveyed more by stained-glass windows than by the elite Latin discourse.

You're right, though. It was technically more a case of mass control than mass consumption. The Catholic Church withheld more information than it conveyed.