As A_C said, Viacom owns MTV, Nickelodeon, and consequently, a portion of HMX now, so what they say goes. Unfortunately for us, what they said was that we need Spongebob songs in Rock Band. To be fair, though, there are plenty of children that play RB and certainly plenty of those same children love Spongebob. I can understand the thinking there.
The base of the issue is that those three Spongebob songs could have been three Muse songs instead.











