Copenhagen was a complete and utter shambles. No doubt about it. Various commentators and participants have been fishing around since it dribbled away to its weak conclusion, looking for someone or some organisation to blame.
The British blamed the Chinese, the Africans blamed the North Americans, the socialists blamed the elitist imperialists, and the NGOs blamed the international companies who had a corporate interest in swaying the whole deal their way, protecting business interests.
One story, much repeated by Climate Change Denier sources, blames the United Nations in effect, or at least the whole of Denmark, for allowing 30,000 Non-Governmental-Organisation (NGO) people to be registered, when the Copenhagen Bella Conference Center could only accommodate 15,000 people.