Agree with her, but remind her that it is a sad reality of life. As long as Mankind is, there will be wars. There is no Utopia. Wargaming is a tool to save lives (yours)as well as take them. Tell her chess is a wargame, should people stop playing that?
Ask her to think about the major wars in history and what life would be like now if they weren't fought, if everybody rolled over and looked the other way. How many Races and Nationalities would be extinct by this time.
How many people would be exterminated for their religious beliefs.
Would the country she lives in now actually exist as she knows it, or could it be worse or better.
brad