I find all of these "social media is bad" articles (for kids or adults) basically boil down to: Let humans communicate freely, some of them will do bad things.
This presents a choice: Monitor everyone Orwell-style, or accept that the medium isn't going to be able to solve the problem. Even though we tolerate a lot more monitoring for kids than adults, I'm still pretty uncomfortable with the idea that technology platforms should be policing everyone's messages.
So I sleep just fine knowing that some kids (and adults) are going to have bad experiences. I send my kid to the playground knowing he could be hurt. I take him skiing. He just got his first motorcycle. We should not strive for a risk-free world, and I think efforts to make it risk-free are toxic.