Cigarettes, liquor, porn, R-rated movies, all had general barriers to access for kids in the pre-internet world. Parents could rely on most store clerks not selling alcohol, tobacco, or adult magazines to a child. Parents did not have to hover over everything their child did. Was it perfect, of course not, but it worked fairly well and didn't require constant monitoring. You could let your kids go to the mall and be fairly sure that they would not be let in to an R-rated movie. They could ride their bikes to a convenience store and the worst thing they could buy was candy.
With online accounts and apps, everything needs review and permission. Every. Single. Thing. That is the main complaint in TFA. He wants a single device level setting so that he doesn't have to constantly vet everything.
This is precisely why many parents support age verification laws for social media and adult sites. Tech companies could have solved this on their terms but they just punted it to "parents" with an insane level of complexity, and the parents don't like it.