Well, non-Islamic countries of South America and SE Asia certainly have a lot of poverty as well as a brutal history of western colonization and imperialism (I'm not sure any other areas have had it worse). Yet, I'm not aware of any violence or murders or beheadings set off in those countries due to provocative cartoons about their gods. I don't see the intolerance like the homophobia, antisemitism and anti-feminism or whatever other minorities there either.
Dance around it all you want, it's a toxic cocktail of many factors, fundamentalist Islam being one of them.
To say that killing someone over a cartoon about Mo' isn't about extreme Islamic beliefs is plain silly.
I'm not sure how Central and South Americans killing each other over drugs, politics or friggin soccer is that different from Muslims killing people over cartoons (nevermind that as Sander says that's a pretty tunnel vision way to think about such things). A corpse is a corpse, it doesn't care why it died for. Killing is not right, unless in the most dire of circumstances. I'm going to say it for a third time because I'm boring like that, but someone killed by a lunatic screaming to Allah is no less dead than some guy from Pakistan being blown up by a Drone. Or in the example you give, Mexican schoolchildren being butchered by drug cartels who want to send a message, or some poor shmuck stabbed to death because he walked in the wrong Favela.
I mean hell, if I recall correctly the war against the Mexican cartels and assorted violences claimed the lives of at least 40 000 people just last year, or maybe it was in 2013. Nevertheless, that's more than the casualties of any Islamic movement by a fairly wide margin, except perhaps if you count the deaths in the Syrian civil war (which is not caused by religion, primarily at least). Let's not act as if conflicts in Muslim dominated areas are much worse than in other war-torn parts of the globe. Hasn't the proxy war in Europe's very own Ukraine reached a couple thousand casualies too?
To be quite blunt, I don't think what shocks people in Western countries is that Islamic fanatics kill because of Allah (or cartoons or whatever). It's that killing infidels in Allah's name means that foreign people we don't care about aren't the only potential targets; these lunatics are also gunning for
us, so obviously they are the worst of the worst.
EDIT: As a corrolary, just to hammer the point home,
this article shows that the West has absolutely no problem praising political leaders supporting radical islamist policies (including Sharia law, beheading criminals and whipping political dissidents) so long as they throw enough oil our way. And people still try to claim that our problem with radical Islam is on a purely moral level, yeah right. It's realpolitik like always.
