Everyone has a responsibilty, that's how society is supposed to work. Of course parents should be able to control their children but they should believe the government, schools, etc, are helping with the basics. It can't be easy stopping your kids having social media if it instantly marks them out with their contempories.
Its a tricky subject and can see why Australia have brought it in as a law, which I think they should do here. One of my bairns has just started secondary school and therefore has her own phone so she can call and message her friends, plus me and her mam as we are separated. Some of her friends have iPhones, some have Android therefore she has access to WhatsApp for group messaging. She's not allowed Facebook, Twitter, Tiktok, Instagram etc but even WhatsApp now has a social media thing called Channels where you can make videos and give people the link etc. Had to sit down and have a conversation about what she puts on there and who she shares the link with, I'll also check regularly who the followers are as you can see that. I like to think I am a responsible parent but in the world of social media, peer pressure and all kids wanting to be presenters instead of getting an actual job it is an absolute minefield and not as simple as people think. Making it illegal for kids, and therefore making the social media providers accountable is possibly the only way to do it.
I'm glad I keep off most social media, the only 2 platforms I interact with where I don't know the people are here and rtg, I use WhatsApp and Snapchat but only with family and friends I actually know