For your example ("the same kind of videos my own sisters would shoot with our dad's camcorder") there are two remedies:
1) Upload the video as unlisted, so it will not appear in recommendation systems and you can send the link to your friends/family.
2) Disable comments on the video.
Public content is a bit more dangerous to leave unchecked in 2019 than in 2009.
The suggestion here is that Youtube should do something about it, and I'm asking what that solution specifically looks like.
This may be an awkward position to take in public, but I'm not comfortable with the idea of criminalizing "creepy comments", especially on the internet.
What sort of advances have happened since 2009 that would explain this?
To me, the seminal event marking the transition has to be IMDB shutting its forums. Public discussion and discourse is now seen more as a liability than something of value.