This may get me moderated and/or hated for discrimination, but I think it's naive to believe that this is just fanaticism and doesn't reflect a problem within Islam.
You don't see mass shootings over cartoons of Buddha, Jesus, or Vishnu.
Of course, not all Muslims are to blame, plenty are peace loving and denounce terrorism, but it's not a coincidence that this one particular religion is the source of so many acts of terrorism.
Islam in its... let's call it "old testament" form is simply incompatible with a modern Western society.