How did the UN (or at least the member states which were involved in this decision) motivate the rejection of the Gibraltar referenda?
Gibraltar is largely a self-governing British territory on the tip of the Iberian Peninsula with a population of about 30,000 people, whose territory is claimed by Spain. It continues to be listed as an NSGT though its residents expressed a preference in two referendums to retain the status quo. In 1967, they were asked whether to retain their current status or to become part of Spain. The status quo was favoured by 12,138 votes to 44. In 2002, a proposal for a joint British–Spanish administration of the territory was voted down by 17,900 votes to 187. (The "no" vote accounted for more than 85% of Gibraltar's entire electorate). The United Nations did not recognise either referendum, with the 1967 referendum being declared in contravention of previous UN resolutions.
Given that the UK has a veto in UNSC etc. (and Spain doesn't), this level of UN opposition seems surprising. Alas the references cited by Wikipedia are dead links. So, how did the UN, or at least the member states that were effectively involved in those decisions (to ignore the Gibraltar referenda) motivate their decision? (Did they e.g. explicitly agree with the Spanish argument that the present Gibraltar population are "imported aliens"?)