The causes of the protests in Afghanistan

(updated below)

Most American media accounts and commentary about the ongoing violent anti-American protests in Afghanistan depict their principal cause as anger over the burning of Korans (it's just a book: why would people get violent over it?) — except that Afghans themselves keep saying things like this:

Protesters in Kabul interviewed on the road and in front of Parliament said that this was not the first time that Americans had violated Afghan cultural and religious traditions and that...