“We don’t believe in killing innocents,” Ramadan Abedi said before he was detained in Tripoli.

It's hard to be sure what this means.  Maybe to Ramadan Abedi "innocents" actually means what most of us take it to mean.  However, to many, many people throughout history who had the authority and means to rain down mass death and destruction on whole populations, there is no such thing as a truly "innocent."  Even killing an infant can be justified to a warped way of thinking if considering them as merely future adversaries to be slain at any time with no mercy. 

"Some of you young men think that war is all glamour and glory, but let me tell you, boys, it is all Hell!" - General William Tecumseh Sherman, June 19, 1879  (More than most, Sherman understood and was resigned to the consequences of war.)