Look on the life of Prophet Muhammad for instance (you'll find plenty of non-Muslim accounts on His life that are non-biased) never you'll find any instance where he punished someone just because he ridiculed him.
Forget about prophet, just when Europe was going through the dark ages and Muslims were building knowledge cities in Spain etc. There were departments specifically reserved for scholars to come and discuss and question each other's religion! It's part of our history books, and a fact.
What we're seeing today is some radical Muslims dominating the majority and just because they have taken up guns people have started associating violence with Islam.
Do you know that the most number of people that have suffered from these extremists are infact Muslims themselves? I'll urge you to dig this further :)
p.s "Islam" when translated to english means Peace. Do I need to say any further?
Abu 'Afak seems close. He wrote a politically charged poem against Muhammad and was killed. Perhaps not just for ridicule, more for political opposition but even so it seems bad form.
Then you didn't read the actual Quran. I will not claim that the Quran is more violent than other holy books, but it certainly has its share of calls to violence.
A more common translation is "submission".
Religions really do cause their hosts to have different propensities for violence.
1. http://www.fas.harvard.edu/~pluralsm/affiliates/jainism/jain...
2. http://www.independent.co.uk/news/world/asia/the-vegetarian-...
After September 11th, I read the Qur'an[1] to see what the fuss was about. I encourage others to do the same. Unlike the Bible, it is not a long text. Even if you take notes while reading, you can finish it in a few days. Unless you're indoctrinated in the faith, it will be obvious that the Qur'an preaches violence toward the infidel much more than nonviolence.
1. Or more correctly, an English translation of the Qur'an.