I made the mistake of giving my child access to Roblox when he was 7, assuming that they did some sort of moderation. Luckily, the worst thing he found was a game that told him he was going to die that night. It scared the hell out of him. After doing a bit more research on Roblox, I decided to ban it from the household. I'm happy that I did, considering it seems that it's just a cesspool of predators.

It's fine and well to say the solution is to just be around more or take an interest in what they're doing, but that is hard to do with full time jobs, multiple kids, etc. Parental controls are supposed to exist to let the parents let their kids explore in a safe space. It's not about constant supervision or tracking, its more akin to hiring a babysitter rather than leave your children home alone.