Like the 'no images of Mo' rule it's all cultural bull. Go into the vaults of Egypt's museums and you will see Arab paintings of Mohammed from the 12th century that were cherished like the Mona Lisa is now.
I think you'll find many many Muslims will be shaking their heads thinking when are these idiot's just going to shut up AND when are the non Muslims just going to start ignoring them.
We offer these cultural extremists the oxygen of publicity and starve the normals Muslims.
There's an old newspaper rule: if it bleeds, it leads.
A small number of people willing to do violence can get and hold much greater press and political power than a large number of people simply trying to get along. Sucks, huh.
Seriously though, do musical renditions of Qu'ranic verses go against Islam in the same way as images of Muhammad?