Christian countries started both world wars. Beligerents on all sides were Christian. If not explicitly, certainly in practice. A Christian country (Spain) completely oblitterated all South American nations. They did such a good job that they managed to destabalize and destroy their own government in the process. The French revolution? Russian revolution? The Roman Empire.
This idea that non-islamism is a guarantee for political stability is dumb. In fact, the Islamic caliphates was for over a thousand years the most politically stable region in the world. In spite of Timur and the Mongols doing their best to end it. So how do you explain that?
I'd argue that the succes of the Caliphate is the main reason the Islamic world today is in such a bad state. Stability at any price isn't always a good thing.
In other words, you can't name an Islamic country not in turmoil.
What's the common factor in just about every trouble spot in the world? Islam.
Bahrain, Bangladesh, Brunei, The Comoros, Maldives, Mali, Mauritania, Mayote, United Arab Emirates...
That's nine; There are a few others that probably qualify, depending on how you define 'in turmoil' and how 'current' that turmoil needs to be - Bosnia-Herzegovina and Albania, for example; and the former Soviet republics such as Azerbaijan and Tajikistan.
It's a neat 'gotcha' question though - most people are not great at geography, so they only remember the names of foreign countries that have been in the news recently, and newsworthiness implies turmoil. So failing the challenge is to be expected despite the existence of many such peaceful islamic nations.
It's a good illustration of the difference between being clever, and being a clever dick. You can win the argument despite being wrong.