> If you do not believe that people should profit from increasing the lethality of the military, then you do not believe in the utility of having a military.

Alternative: You can believe that circumstances dictate if the military is doing good or bad things. If the military is doing bad things, it is a reasonable argument to oppose them. Clearest example is Yemen.

A less clear and debateable example is: the excessive size of the US military may cause other countries like Russia, China, North Korea, and Iran to build up their own militaries to defend themselves when they would otherwise reduce their military spending. In some cases, mutual disarmament can work, however, it hasn't been tried sufficiently hard (e.g. USA hasn't ever proposed reducing its number of aircraft carriers by treaty, so carriers require asymmetrical warfare capability in order to deter aggression from USA).