User blog comment:EthanConquistador/Holiday in Malaysia = Copyrighted music not available for my iPad/@comment-26847796-20140130091729/@comment-6812733-20140130143419

That's like asking why is robbing someone a crime. Because it's using someone without the victim being able to do anything about it.

In other words, content owners have power in YouTube so that they can protect that is rightfully and lawfully theirs. Just like civilians can protect what is rightfully and lawfully theirs by having police forces to help them.