Oh that is an easy one. That US accusation was actually open speculation by Indian and German researchers examining the only data that China was willing to share with the rest of the world. They weren't accused of intentionally unleashing it, but negligence was speculated - the lying and secrecy is the cause for that, and they have only themselves to blame. China had allowed only one outside crisis team in, from the WHO (which lost credibility long ago) - and they only spent a single day in Wuhan. Around that time it was discovered that China had been under-reporting infections by an order of magnitude, every province coincidentally made the same calculation error for the same period of time.
> ...they're fairly common tactics worldwide.
This is all unprecedented. We have never seen such transparent lies counter-messaged in near realtime by way of opensource intelligence. Grassroots btw, the corporate response has been denial - followed by a week or two of softening messaging, then admission to the truth. The information surrounding cross species transmissibility is a good example: videos starting popping up of Chinese people hurling their pets from rooftops in response to government warnings with regard to transmissibility. The corporate media immediately swung into action, declaring any such talk as racist FakeNews™ - but they were wrong again.