Barbarians: Culture or Religion?

It seems to me that it is unarguable that the following are barbaric acts:

Rioting over cartoons.
Killing a non-because the Pope suggests Islam is violent.
Suicide bombings.
Taking hostages and beheading them.
Killing converts to Christianity from Islam (thus assuring that they will never convert back, I guess).

Are the people who do these things barbarians because of their culture? Or because of their theology? That is, what causes the barbarism?

Now we learn that in Muslim Pakistan, kite flying is a popular pastime. However, the kites are often flown with strings laced with ground glass and metal, which may and often do kill other kite flyers. In the last few days, at a kite flying event, 11 people were killed. see DebbieSchlussel.com

Barbaric? Of course. I wonder if the Islamic resistance to social change is partly to blame for the barbaric culture displayed.