G.I. Jesus?

I hope the title doesn’t upset anyone, but I wanted to get my point across quickly. Other titles I considered were “Rambo Jesus” and “Who Would Jesus Shoot?” (as a play on What Would Jesus Do?). My point is this: Can you picture Jesus Christ dressed for combat (or perhaps only half dressed Rambo style) carrying an M60 machine gun ready to blow away His enemies? No? Then why do so many who name the name of Christ think it is perfectly fine for them to join the military and either directly participate in or support the killing of thousands of people in wars? And why do so many politically active Christians think it right to support or even lobby for war?