I understand what you say, I also see it as unfair that some countries have it and others do not. It is the same as when talking about regulations for global warming, and is intended to prevent less developed countries from building greater industrial capacity.
But we must also understand the danger of a nuclear weapon falling into the wrong hands, which in turn is better to prevent more countries from embarking on a nuclear program.
The best, and what the world powers are presently doing, is to try to create a system that can neutralize the deployment of nuclear weapons.