Experience (see Facebook, in general, and the real name experiment) says that no, your last point does not hold. As it turns out, people are more than happy to be assholes with their names attached, never mind the many others who don’t want to make drama and are more than happy to keep hanging out with them.
If you roam around the internet for long enough, in the right public areas, you are bound to find plenty of tales of families choosing to keep hanging out with abusers over the victims, never mind people who are just “being mean on the internet”.



I really don’t think the article makes a good case for why they are using “withdrawal symptoms” (which clearly evokes drugs) beyond being a nice quote. Could the behavioural issues be, say, kids figuring out what to do (or what they can get away with) now that what they used to do is no longer available? The article certainly doesn’t say so.
The other thing is that these are things that are taking years to play out, which suggests to me that there may be more than just cellphones in the classroom. There is certainly a point to be made that if the smartphone is still used at home, you may up in a wash anyway. A reductive scenario I could think of, for example, might be that a student may say they are more attentive, and they may look more attentive, but if they aren’t really engaging with because they will just go home and ask an LLM for the answers to the homework.