It would be easy to go tit for tat but given the current crazy situation happening in America and how China is avoiding anything to do with the domestic side of things in the USA, China is reciprocating by letting them continue to blame them while they ignore all the issues (fires, hurricanes, bankruptcies, pandemic, post office, etc.) that is rapidly building up and becoming more and more difficult to deal with in a short time frame. Given that the US is failing in every sense of the word in handling there own problems (heck, even the stimulus package extension hasn't been passed though) they are basically helping to advertise to the world how unstable the US is compared to China, something that in the coming months, more and more nations around the world will take note of if you see how most European countries are starting to turn away from the USA (especially when Pompeo blew up at them a few days ago) and also how the USA are basically hated in Africa and South America,. Basically, the USA is helping to advertise to the world how unstable there democracy is compared to China's leadership, hence, this arrangement is going to be a case of short term pain for long term gain (with the side benefit of crumpling the USA without firing a missile). Also to note is that while there are nations that want to fight China, none of them have the balls to really start a fight given that consequences is simply too high and they know very well that the US will never back them up to the end (they did abandon the Kurds just recently after all). Also to note is that if the US was reasonable enough to ask China for aid, China may have assisted them, but given the current situation, there won't be much to save them from this sinking ship hence I don't think anyone is interested in helping America right now, other then isolating them so they don't spread the virus further.
