Many UX patterns are fine tuned to keep people in more, which is perfectly understandable as the primary goal is to keep the user in.
Now, who defines "addictive" using which aspect? And even if it is defined, how are they going to outlaw "addictive design"? Blocking UX patterns? Imposing a limit on how quick a user can swipe to next content (which would do more harm than good in general)? Limiting displayed relevant recommended content at the end of content (again, more harm than good in general)?
Don't want to play devil's advocate here but it's not the apps'/platforms' fault here, but parents' fault.
Sugar is addictive. Do we ban sugar, or regulate its consumption? No! Instead we educate parents to limit their childrens' sugar intake.
Parents need to be educated the same way about addictiveness of social platforms and limit their children's usage, but they are probably perfectly okay with status quo as giving a tablet to a kid "snoozes" them for hours so the parent can do whatever they want without interacting with their children, which is wrong in the first place.
I do not work for any big social media platform nor benefit from them, but stop blaming successful social media platforms that have mastered UX optimization, for stupid parents' actions that cause their children to get addicted.
Educate the parents instead to spend more right time with their children.