Well, yes, the peer pressure and possibly the deep rooted insecurity you are talking about, and FOMO / the fear of isolation / being excluded. That's actually a big part of the issue.
(as someone who has always resisted social networks except HN for various reasons, pretty sure it's a net positive, but I've known since the beginning that interactions happened there and I was excluded from these)
I know I cut your sentence mid way, but I believe that reacting to stuff you see when you are there is probably only natural.
Peer pressure is forcing them.
Yeah, you can say they should just ignore peer pressure and such... but if say, 90% of teens had smoking problem, would you just shrug and say well nothing is forcing them to take a cigarette?
Honestly, you are right on every point, A) you don't need to live your life on social media, B) once you do you get sucked into an increasingly weird and unhealthy point of view & behaviors.
The only way to win is not to play. Read books instead of doom scroll. Meet friends in meat space, don't text. If they get all unhinged about transgender Hamas rights or whatever the current Reddit/X tempest in a tea pot is, just go "Oh yeah that sounds serious, tell me more" and then change the topic after 60 seconds - that's going to be the upper limit of their attention span anyway.
It can be done, you can unplug, you lose basically nothing by doing so, and you gain the world, life gets better. Unplugging from endless online BS, simply refusing to participate, improved my focus, attention span, made me smarter because I read books instead, freed up time to start hitting the gym which led to a 15 point drop in my blood pressure, the list of positive benefits goes on and on. I once was an optimistic futurist, I now have serious, serious reservations about the impact our industry has had on society in the 21st century.
Tell the kids, it was better in the old days before Meta.