Your argument is absurd... we have real world counter-examples. When people were complaining about the recent Iraq conflict (and Afghanistan too), the complaints were always "not enough boots on the ground". Turns out that what wins wars is men with rifles. Not tanks, battleships, or next generation fighter jets.

Worse than the logic of your argument, is the morality of it. If trained soldiers are oppressing people, then not only is it rational to retain the means to fight back against them, but it's a moral imperative. Stupidity might be forgiven, you can't will yourself to be smarter than you were born. Moral cowardice is a choice, a disgusting one.