Majority of who, exactly? Where is the boundary of the dēmos from whence the word "democracy" comes?
Is it even constant for all things, or should powers of self derermination shift as group sizes change: what power should the people of California and New York have to tell the people of Texas that there are decisions they cannot make? What power should the USA have to tell Russia or Ukraine what to do?
Because the US is a minority of the world. So is the EU. So is China, despite being larger than both combined.
Half the world lives within 3300 km of Mong Khet, Myanmar; should they determine all world rules down to planning permission, or just global matters such as mandatory climate change reaponses and enforcing global treaties?: https://en.wikipedia.org/wiki/Valeriepieris_circle
Not really shocked such a take is contradictory in and of itself.