There's a civil war before between Syrian president Bashir Assad's government forces and ISIS. ISIS wants a global caliphate (look up caliphate, it's peachy). Assad is backed by Russia. The west does not support either Assad or ISIS (obviously) if ISIS takes both Iraq and Syria it becomes another lawless safe haven to launch 9-11 style attacks on the rest of the world (Afghanistan memories?) No one is bombing civilians, they are bombing militants. The militants use 4th generational gorilla tactics I.e no uniforms for the exact purpose to confuse their enemies, when average people who are not educated on this type of warfare see them they believe they are civilians.