TV, print, radio, music and to a lesser extent games are all subject to some level of industry or statutory content regulation.
For example, in America, you're very unlikely to have a kids TV channel suddenly switch to videos of people being killed in industrial accidents. new media, not so much.
Watershed, age constraints and company ending fines existed (and in some cases still do) for violating those rules.
Large new media companies, such as facebook, youtube and tiktok can literally serve porn to kids and not have any legal ramifications. If a cable broadcaster knowingly broadcast frontal nudity before watershed, it would be fined. (yes, cable TV has less restrictions) but thats the point, regulation has not kept up with the pace of change. that has been a deliberate decision.
My kids are >5 < 12. They aren't allowed on insta/tiktok. They can have youtube, but its only when supervised. even then its 1/3 chance that they land on something toxic as shit.
The world has changed, and the guard rails that we had as kids have been removed. There is an argument about freedom of expression, I get that. But we need to think about whether its right to allow large corporations to profit from showing horrific content to minors. (adults, I don't give a shit, do what you want) The problem is, I'm not sure of the best mechanism, with the least bad outcome.