I mean, even when I was a kid and kid websites existed, kids absolutely went into places online that weren't for kids. But it caused a lot less societal problems when those sites weren't massively relied on by adults and teens, and there were actual spaces intended for kids where like 90% of kids spent a good 80% of their online time. And it's not like those kiddie sites weren't monetized and built to get kids to beg for Mom's credit card, there was a shit ton of paywalling features behind premium memberships you had to pay monthly for. But you could generally have an alright experience for free on the less predatory ones, at least. And capitalism made even that model no longer viable.

(As an aside, rants about how capitalism ruined the Net often set me off imagining if we hadn't lost the Cold War and if the Soviets had come up with the Internet before the West did. I think it'd be a way better place. We might have just as much centralization but it'd be state rather than corporate, which might suck a bit less, and the political leanings and party lines of today's small leftist sites would be the default, there'd be small explicitly neoliberal-capitalist sites referred to with derogatory terms by the rest of the Net.)