Maybe it's old fashioned of me, but I think viewers are responsible for their actions. YouTube is such a wonderful resource, and it seems terrible to judge it on this basis. It's like judging a library that happens to have chemistry books that kids misused to hurt themselves. The problem isn't the library, or the book.
(Note: its different with political/emotional content. That stuff is more like a virus.)
By all means, I agree that everyone should be responsible for their actions. It is by this same principle that I believe that YouTube should be responsible for what they publish. The "the problem isn't the library" argument falls short if the library is actively banning books that offer information on the hazards and risks of the "how to manufacture large amounts of chlorine gas using just kitchen appliances" books they happily put on the shelves.
I don't know how old fashioned that is. Before the web, you didn't stumble upon this kind of content, and it was certainly not promoted to the top of anyones feed.
(Note: its different with political/emotional content. That stuff is more like a virus.)