Well that's a good point. It's the difference between the ideal of the UN, vs. the reality of the UN. It's supposed to a fair global venue, but because it lacks any self-sufficient authority, it's dominated by the most powerful nations. That said, China is one of those most powerful nations, so I'd argue that this ruling still has significance.
Maybe someday there will be an actual global government, but right now I don't think that anyone believes we (i.e. human beings) know how to create a well-functioning government that large.
The EU suffers from many of the same problems of the UN, like crazy bureaucracy and dominance by the largest/richest member nations. The U.S. federal government was carefully designed to balance small states and big states, and seems to do a good job of that--but maybe not a lot of other things. And big U.S. states still dominate other areas of national governance, like environmental regs by California, or school textbook standards by Texas.
