Their argument is that there are randomized control trials that show that, compared to control, social media indeed causes harmful outcomes.

Trouble is, those RCTs are laughably bad.

They’re:
SMALL (often tens of subjects).
BRIEF (sometimes 20, 7, even 5 minutes long)
Not blinded (subjects know what the experimenters expect to find)
Not representative (rich college kids)
Not relevant (test conditions are not anything like social media use).