In my opinion, the situation where only a few powerful countries with quite stable institutions have nukes is better for humanity than the situation where every country has their own nukes. Just consider the number of coups or wars going on every decade: if everyone the incumbent leader knows that they can just press the red button and wipe out their opponents, of course it would en up happening one day, and could trigger a chain reaction.

This risk of "president goes mad" (don't look at the button Vladimir) is minimal when as few countries as possible have nukes.

Of course, this goes against the social justice between countries - but wait, does that concept even exist?