Us? Violent?!

So the Pope discusses some obscure 14th century writings in a dry, scholarly speech. In the writings the religion of Islam is referred to as violent. Muslims get offended, riot, firebomb a couple of churches, and kill a nun by shooting her in the back three times. Whyever would anyone consider Muslims violent?

The reaction in the Muslim world is so out of porportion to any real or assumed offense that how can it be viewed as anything but violent?