"But, he added, UN Security Council and not the General Assembly is the ultimately deciding body on the matter." No, it is the UNSC that ultimately decides that the state of Palestine can join the United Nations. Nothing prevents the UNGA voting on a resolution that recognizes that the West Bank and the Gaza Strip is a sovereign state under occupation, and not a stateless territory, and the UNSC can do nothing to prevent that vote taking place. That the UNGA can then invoke Res 377 to come to the aid of that (occupied) state is, again, something that the UNSC is powerless to prevent.
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from the article: Deputy FM: At least 60 UN states back unilateral Palestinian statehood