India & China make up 35% of the entire worlds population. A fair system will admit a lot more people from those countries than others simply because there have more people.
If whole of Europe gets a single EU passport, does it suddenly make them any less diverse?
If race does not matter, then why does "diverse" mean as many races as possible. Shouldn't it mean diversity of thought instead? If nationality does not affect personality, then why should diversity be about diversity of nations?