China has a population density only 4 times the density of the US and half the one of Germany. It has a vast amount of wildlife. Why wouldn't they have any wild animals left?
There's also the fact that upwards of 80% of that popoulation is eastward of a line running roughly from Peking to Canton.
Because they're even endangering animals in other countries and continents, so why not their own as well?
Many are trafficked from Africa. Rhinos are almost extinct thanks to Chinese demand for their horns.
African Pangolins are now critically endangered thanks to Chinese demand.