China has economic competition. If China’s economy gets shut down and no one else’s does, that’s bad for China. All China has to do to prevent that is say nothing. Short term it looks bad. Long term it secures that vulnerable market share. Whether you believe it to be a bad idea or not is irrelevant. People do things that are bad ideas all the time but generally because they believe them to be in their best interest. Governments have done far worse for far less to gain. As mentioned above, many believe our own government has done the same. Are the Chinese incapable of making this sort of gambit?
We'll never get someone from the Chinese government publicly admitting to it, so the best we've got is speculation. His argument is that it makes sense for them to do it. I don't think so.