I think it is not useful to reduce the reaction to the film Innocence of Muslims as purely and singularly rooted in religious offense. These behaviors and reactions are embedded in a complex causal nest of many factors, of which American involvement in the Middle East surely is one. But setting that aside is anyone surprised that with the exception of the Americans in Libya the people killed in these riots themselves are Muslims?
To me if there is such a thing as Islamic civilization*, which expressed Muslims anger, then it has a sociological analog to toddler rage. On occasion an angry toddler decides to make a big fuss over an slight, and then manages to injure themselves, and tarnish their own dignity in the process. This is what seems to be the case when the Islamic world decides to get into a frothy rage about the latest offense.
* I dislike the catchall “Islamic civilization,” but Muslims use the term, and there is an organization of states united by the banner of this religion. There is no such analog for Buddhists or Catholics, to my knowledge, so I think the term has utility.