Literally the US can dictate what kind arms they can develop. It is required they comply to receive consideration for US military aid and to remain under the US nuclear umbrella (from other nuclear armed countries like China, India, Russia, etc...).
Those countries also don't want to spend too much money on their military. So they can't develop nukes, their citizens don't want that. We actually want them to spend more, not less, like Japan. South Korea actually built automatic turret guns that shoot without human control. So I call BS on the evil us wants to stop them from building robots.