4 chan is the al-Queda of the Internet. there a bunch of extremist assholes who are so desperate to prove that they are still relevant and have power, that they are willing to ruin the minds of perhaps thousands of people to do it. don't believe me?
I'm gonna go out on a limb and assume most Justin Bieber fans are women. young women, most of them perhaps no older than 10 or 12. now, I dunno if you would want your 10 or 12 year old sibling looking at shock pornography, or being told that their flavor of the week just died in a car crash. 4-Chan is, as it always has been, a group of Trolls who wanna fuck with you for the lols. my advice would be for Youtube, and everyone else, to Ignore this and 4chan completely. Remember kids, Don't feed the Trolls.