There might be those with good intentions who participate in United Nations' debates and votes, but for the most part, the organization is useless. This is easily demonstrated. It is supposed to be an advocate and force for world peace, yet there have been multiple wars in progress throughout the organization's existence.
And when it comes down to it, does anyone really believe that if some of the world's major powers were determined to go to war that a vote by the UN would deter them? Even more ridiculous is the idea that it can force nations to disarm. At best it provides physical space where belligerents can hurl insults at each other with little fear of violence breaking out on the spot.
At worst, it's a waste of time and money, and provides a false hope to peoples and nations that really would like to live in peace.
It's current vote on banning nuclear weapons is an excellent example.
More on this vote on page two.