Or it could be that it doesn't fit into the age demographics. Not many studies on child behaviour are conducted at the Bingo Hall.

This is an ignorant assumption about the author's motives that doesn't withstand even the least bit of scrutiny. Meta came first under Haidt's crosshairs and has been targeted since this article was released. Snapchat was targeted with a partner piece to this one yesterday:

https://www.afterbabel.com/p/industrial-scale-snapchat

Haidt isn't anti-China, he's anti-all-social-media.

Meta has towering mountains of criticism and legal issues against them. For the most part it just doesn't involve kids, as kids don't really use their platform.