Because youtubes primary purpose for existing doesn't depend on copyright infringement. MU was raided because of their alleged blatant infringement and non DMCA good faith compliance.
I suggest you read the evidence in Viacom vs YouTube, their founders admitted as much in internal emails that most of the early traffic was copyright material.
The real answer to my hypothetical question is that there is no difference. One just happens to be run by a German hacker while the other by upstanding citizens of Silicon Valley.
One beat a civil lawsuit while the other has the full force of the US government trying to lock him up for life with a criminal conspiracy case (a bullshit law used to catch mafia figures).
Kim is not a hacker. At least he wasn't when the media declared him one, as he had never written a single line of code. Maybe he learned something since then, but I doubt that. His talents lie elsewhere. He was very good at deception - he somehow convinced a journalist that he was able to hack a GSM phone for example. Or convincing mobsters to invest in his pump and dump schemes. If you understand German, you can follow some of his interactions with the German hacking crowd at http://arnold.babsi.de/KIMBLE.txt. It's not pretty.
Yeah. The scuttlebutt at Google when YouTube was purchased was, "great, but what about when we have to take most of its content down for violating copyright?"
