We don’t know that. As per the webpage, this could’ve been uploaded directly from the Photos app on an iPhone, by people who didn’t really understand the consequences. Maybe they uploaded it and thought they’d get a private link to share with one specific person. Most people are not tech savvy and don’t fully understand the possible ramifications of their sharing.
Yeah I just got a video of an infant taking a bath. I have small kids my self so nothing new, but not something I would want on the internet for everyone to see. And I doubt that the mom, and now the teenager who was the kid, would want broadcast everywhere.