I gues the point is that you as a parent should answer that question irt the children being exposed to the internet in general.
Its not just about 'social media', but about content (video, audio, writings), online gaming, etc/whatever.
Its also not just about how much of the world you allow your kid to see and interact with, but also how much of your kid is exposed to the world.
'Should kids be on social media' is a fair question, but very limited in scope compared to all the things we need to come up with answers for.