Bottom line up front: they're attacking WHO for failing to do things that WHO...has no authority to do.
state.gov/secretary-mich…
WHO's authority w.r.t. novel outbreak crises is enshrined in the Int'l Health Regulations, a legally-binding agreement amongst WHO's member states. who.int/ihr/publicatio…
This might sound frustrating, but flip it around: how would the USG react if WHO told us they were opening a unilateral investigation in our country?
Nada. Nothing in the IHRs grants WHO the authority to do this.
The closest thing that exists in int'l law is in the bio weapons convention - but that 1) isn't WHO, and 2) does't apply here.
Which is essentially what they're demanding WHO do here.
Yes!
But then the solution then is to amend and update the IHRs (long overdue, frankly) rather than pillory WHO for adhering to them.
But it's hard to turn an inanimate int'l legal instrument into a political scapegoat. And a rallying cry of "reform the IHRs!" doesn't give Trump much political cover.
So WHO gets the flak.