I think you will find a lot of the airline response in dropping flights to China is largely commercial rather than benevolent at this point in time.
The Chinese government has banned group tours and largely outbound tourism, which I imagine is making up a large amount of passengers generally taking these flights - especially in the CNY high season right now.
If you take away the outbound tourism aspect from China (due to the government restrictions) and the inbound travel aspect from other countries (due to businesses/universities/governments restricting travel for their staff, it's a good scapegoat for airlines to drop services which are almost certainly loss making. ??Load factors both ways dropping off a cliff is already an anecdotal scenario.
That combined with the duty of care aspect for flight crew operating and laying over, and any ground staff that they may directly employ in these foreign stations... a legal issue may begin to arise too.