I get what you are trying to say. But my life would not have been the same without South Park. And I mean that in a serious and positive way. I'm in my late twenties now and I've been watching the show since it's beginning.
You're comparing a well written, comedy driven, socially critical, 18+ advertised cartoon made and created by two famous comedians, with that youtube bot-like harmful garbage stuff intentionally aimed at a kid audience, created by some very sketchy unknown people on the internet. This is nonsensical. With all due respect, you can't compare apples with oranges.
While South Park may have said it was for mature audiences, you yourself were the audience, and many other children were as well.
I know that children can deal with life and death issues, as I did. However, they are impressionable, and parking kids in front of Youtool or a tv, is akin to setting a sponge in a bowl of water.
They absorb culture, as people always have, by watching people, and their brains do not know the difference between people on video and real people, even if they themselves do. They can consciously know that the people on the tv are actors in a fictional program, but their subconscious absorbs the cultural cues anyway.
Books don't do that to our brains.
Read books, but more importantly, make sure your kids do.