On the other hand, 'Social media damages teenagers mental health' sounds a lot like puritan arguments against rock music, weed, and video games from decades past. All of those things had legit studies done on them that showed harm, too. Honestly I think the kids are gonna be alright.
Well, sometimes they get things right, like (only stretching slightly) alcohol, which is not great in excess. You have to consider these things individually rather than trying to draw generalizations like "all puritan backlash is wrong."
My argument isn't really "they said these things were bad and they're not," it's more like "these things are actually kinda bad in some circumstances, but mostly we all turned out ok anyway, and things wouldn't really be much different or better if rock music were more heavily regulated when we were kids."