Is religion cruel and drive someone to resort to violence instead of peace? Yes, an atheist who are bored to be religious might say.
One should not forget that an urge to go to violence is here within one’s heart. And human has a tendency to justify whatever one does to hide one’s true intention. And what the most legitimate reasons other than the reason of religion?
Hence, history witnessed the religion’s based ware in the Europe. Now, many terrorists, who claim to be Muslim, wage the war against anyone who doesn’t accept their ideology.
Anyone who cannot make peace with himself will always try to wage violence with or against others to satisfy his lust of doing violence acts. With or without the name of religion.
If you like writing about Islam, you might want to search for Quranic verses or Hadith (saying of the Prophet Muhammad) as your reference. With internet technology, what you need is a click of the mouse. Gone were the days when you have to sweat it out opening some very thick books of Quran and Hadiths to find out relevant references.