However, there was also the Albigensian Crusade and not a single piece of catharian writing survived this.

This is false. The "Liber de duobus principiis" survived.

Mind that this originated from a diverging faction, written about 1240, essentially after the crusade (1209–1229).

well that and the entire Mayan corpus.

what pittance of codices we have today come from Christianized Maya scribes, a massively condensed post-columbian highlight reel of their obliterated textual culture compiled at the behest of the Spanish crown and under the direction of their Catholic overseers.

Also, languages like Guarani survived because of the efforts of missionaries (the Jesuits in this case).

(But I will say that the current policy of "protecting" the isolated tribes in the Amazon from human contact by categorically shutting them off is quite horrible and uncharitable. This is rooted in the preposterous myth of the noble savage. Tribal peoples are not innocent children.)

> the current policy of "protecting" the isolated tribes in the Amazon from human contact by categorically shutting them off is quite horrible and uncharitable

I dunno. If you make contact with them, most of them will die of diseases to which they have no immunity. This happens over and over. Amazon tribes. Pacific islands. On a huge scale in the Americas. For those that do survive, the event may be so traumatic that they develop a very understandable hostility to outsiders.

I'm not sure anyone would thank Bishop de Landa for burning the entire written work of a thousand year old civilization.

Disrupting a cycle of ritualized torture may find some support on humanitarian grounds, but it was no excuse to annihilate the rest of Maya literary culture as well.

To be fair, that was also during the Counter-Reformation, or somewhat afterwards. Even if it was unrelated to the Counter-Reformation itself.

Books were still hand written and centralized, they’d have been burned such that we aren’t aware of them today - doesn’t matter if it’s 15th or 17th century