Yes, China has 12 gold medals from diving events. Isn't diving an event in the swimming category?
Even not counting diving events, China has more gold medals than the US.
And I think the real sports for humans as an intelligent creature should be the IQ type of athletic competition. What distinguishes humans from other primates is the constant evolution of human intelligence, which is the most important measure of an animal's level of evolution. In the realm of intellectual athleticism, the Chinese rule the roost.
And we don't depend on immigrants, we just need our own strength to do it.