There is mounting evidence that social media harms mental health[1]. I'm pretty sure when links between smoking and cancer were being established, there were plenty of people calling that evidence "unhinged", particularly if the evidence hurt their paychecks. Not saying that such people were willfully malicious, but that there are strong cognitive biases in favor of ignoring anything that can hurt their livelihoods.
https://www.afterbabel.com/p/the-teen-mental-illness-epidemi...