This is because of political correctness.All flights from China should have been stopped,and Chinese people banned from travelling.
Also,its because of the disgusting eating habits of the Chinese.Its thought this virus comes from eating bats.Among animal populations,there are many viruses that exist that those creatures have evolved to live with,yet if another species,say,humans,encounters it,it can mutate quickly and become lethal.This is down to wildlife crimes that no-one tried to stop.