These people either forgot or were never told that the internet is NOT real life and that it's not recommended to post anything under your real identity and/or in a public place, and especially not things that could get you in trouble like that disturbing shit >>557736
, or what's your political opinions, shit talking your current employer, insulting/harassing/threatening anyone, etc. Especially because the internet never forgets and it's super easy to archive pages and websites.
It's amazing how just 15 years ago parents, even the ones who weren't tech-savvy at all, would yell at their kids that posting literally anything ever would bring viruses to their computers and they'd get kidnapped, tortured and killed by pedos, now if you know where to look you can find out someone's address, employer, who they voted for, who they have or had sex with, who they're related to, where they went to school, etc. in 10 minutes. I managed to do that with people I know irl and who should know better without even trying, it's just that bad.