Everett made up this whole narrative about the Piraha as an attack on Chomsky's linguistic theories, which are almost single handedly responsible for causing the academic reversal that stopped treating people like bags of meat to be slaughtered and started treating them like human beings whose creative drives should be supported.

Needless to say, Everett's attacks failed and are not taken seriously by the academy. Everett was trying to find a counter example to disprove universal grammar, which is the idea that all humans are capable of in principle of learning any other human language, that is all languages are basically generated as variations from the same basic elements, which have a rational structure that correctly relates to reality.

What is at stake: If Chomsky's work is overturned, then we basically go back to Vietnam-era global politics, where people don't have individual existence apart from the involvement with the state (all people are property of the state) and there's no possibility of mulitcultural societies (there must be one culture and one language to rule and dominate the whole world for its own good). However, overturning Chomsky is impossible unless the world goes full deathwish stupid, thanks to the power of his observations and rigor of his theories.

2 Major points of Chomsky: You can raise a Japanese baby in New York and it will learn english very easily. Tabula Rasa mind means a dictator could fill it up with all kinds of bad stuff.