The author explicitly says: "For what it's worth I've reversed the Instagram, Facebook, Reddit, and Twitter apps. They don't collect anywhere near the same amount of data that TikTok does, and they sure as hell aren't outright trying to hide exactly whats being sent like TikTok is."
Last year there were articles about how Facebook sdk collects data from each app that integrates it, even before you login with Facebook. To me it still looks like a much wider data collection than what a single app can do.
being closed source does not mean we can't analyze its behavior. the recent revelation of tiktok's clipboard watching? what were they trying? waiting for some unsuspecting password-manager apps?