War is a great game for the ruling class because we're the ones who pay its terrible costs. The capitalist war machine sends the sons and daughters of the American working class to fight working class people in other countries. When they return home, our veterans' physical and mental wounds are left untreated. They suffer disproportionately from unemployment, homelessness, and suicide. Added to this is, as you mention, the catastrophic financial burden of war: trillions of taxpayer dollars that could be better spent on providing jobs, education, housing, and medical care here at home. Ironically, it was a Republican (and military leader), President Dwight D. Eisenhower, who spoke most forcefully against the cost of war: "Every gun that is made, every warship launched, every rocket fired signifies, in the final sense, a theft from those who hunger and are not fed... The world in arms is not spending money alone. It is spending the sweat of its laborers, the genius of its scientists, the hopes of its children."
CPUSA is not a pacifist party. Communists fought heroically against fascism in the Spanish Civil War and in World War II, and we support the right of oppressed peoples to engage in armed struggle for their liberation. What we condemn, what we organize against, what we fight to end, is a system that squanders the blood and treasure of the working masses to keep the world, not safe, but profitable for the capitalist class.