I at least skimmed all of the meta-analyses that both of them cited. It seems like social media has both positive and negative effects on people, and these average out to fairly near zero.
From this, I can make a hypothesis about why you are seeing what you are seeing: Assuming you are in a society which values hard work, (like the US) then the people around you probably think of social media based screen-time as being lazy. Thus they derive some amount of self-loathing from their own social media use, and are more likely to focus on the negative effects and not the positive effects of social media use.
I don't have the data to prove this particular story, but hopefully it at least demonstrates how both the research and your personal experience could be true at the same time.
"social media has both positive and negative effects on people, and these average out to fairly near zero"
Is that the right way to think about it though? Opiates have many positives (medical pain management) and many negatives (drug misuse and overdoses). Do we simply say "the effects average out so there's not a problem"?
I do think it is worth considering how social media effects people at a more granular level. For instance, I think the focus on "engagement" probably makes the negative effects worse, and we would see less negative effects if social media companies weren't optimizing for that.
However, my understanding is that Haidt wants to completely kick kids off of social media. This is a bit different from how we engage with opioids, which are still used for pain management. Opioids only really have positive effects for pain management, and so I think that it is reasonable to keep them regulated. (although I've heard grumbling from doctors about how them trying to be careful about who they give opioids too leaves a lot of people in severe pain) On the other hand, social media's positive effects are things like staying in touch with old friends, building community with people like you when people around you hate you, and learning new skills. I don't think that restricting or eliminating social media use will help here. Instead I hope that people take the design of social media more seriously. (for instance, HN or Mastadon)
EDIT: additionally I'd say that the negatives of unregulated opioids do far outweigh the positives, which is not the case for social media.
From this, I can make a hypothesis about why you are seeing what you are seeing: Assuming you are in a society which values hard work, (like the US) then the people around you probably think of social media based screen-time as being lazy. Thus they derive some amount of self-loathing from their own social media use, and are more likely to focus on the negative effects and not the positive effects of social media use.
I don't have the data to prove this particular story, but hopefully it at least demonstrates how both the research and your personal experience could be true at the same time.