Religion is Law
God commanded Joshua and his army to attack the people occupying the Promised Land. There have been wars and armies in the Bible, some even supported by God.Does God forgive soldiers? They are simply doing their job in order to protect us.
If you look at the Ten Commandments, it says "Thou shalt not kill." The Jews say it should read "Thou shalt not murder." Self-defense is not murder. Certain situations may arise that may require you to take a life, i.e., if its your life or your children against his or hers or them. Sometimes some people will not be stopped except they be be killed. The jihad as it is practiced among some requires your life and sometimes theirs through suicide attacks. Shall we just ask them politely to quit, do you think that will work?