The followers of radical Islam (ISIS, et al) believe that they will reap eternal rewards by committing horrific acts against the infidels.  They concentrate on that "ultimate reward" rather than recognizing the "earthly" harm they are doing to others.  They believe that , as you put it, "the good can and often does make up for the bad. "  Over centuries, Christian zealots have taken an all-too-similar approach as they "coverted" the heathen.  "Come to Jesus, or die."  Religious zealotry, IMO, has led to truly evil acts far too often.  

I don't care what you believe....that's your business.  However, if a religious person justifies either an evil act or the acceptance of tragedy as the "wish" of god, you lose me.  Mr. Trump claims to be a "Christian"...I ask "Can a true Christian be as self-centered and uncaring as Donald Trump?"  wow, I certainly hope not.  I try to live by the Golden Rule..."do unto others as you would have them do unto you."  ...secular humanism works..  Gary Crum