I disagree that legislation can't help. Fundamentally there's an education disconnect and unnecessary friction in setting up parental controls. Governments can better educate parents about the risks, and give them better tools to filter/monitor content their children watch (eg at the device level). Being a parent is hard and it's possible to make this part easier imo.

eg consider child-proof packaging and labeling laws for medication, which dramatically reduced child mortality due to accidental drug misuse.