TLDR: While Fediverse won’t directly serve you ads, anonymous bad actors other than Meta can save, redistribute, and even dox you for any information you post here. Anything you post here can/will remain forever on some malicious instance that doesn’t honor deletion requests. So be careful!
Yes - of necessity and by design, there is and can be no central authority in the fediverse that can be meaningfully expected to promise to protect blithering morons from the consequences of their own actions.
Whether or not people actually do face the fact that posting publicly things they want to keep private is bash-yourself-in-the-face stupid,
and make the simple choice to simply stop doing it, is entirely, as it should be, their concern.