To be blunt: If you are going to imagine divinely endorsed genocide, you should not imagine yourself as Joshua but as the unfortunate Canaanite whose entire family and village have just been murdered. Instead of always seeing yourself as the cowboy, try being the Indian sometime. Imagine yourself as a Pequot Indian instead of an English colonist. Try being the Lakota Sioux instead of the American cowboy. Do that and then ask yourself how you feel about justifying genocide in the name of God.