Earlier quoted context omitted.
Your thesis here is that all the layers of the public health system would just shrug their shoulders in the event of an unexplained cluster of sick people. It's unrealistic.
No, their thesis is "There is almost certainly community spreading in the US that is going undetected," which is based on observations that the US is doing less testing despite having much greater populations and higher incidence of risk factors. Do you contest that statement and its supporting arguments?
For testing capacity to matter, there would need to be known clusters of suspected cases...if you have known clusters of an unknown disease, "undetected spreading" isn't exactly the situation you are in.
I apologize about the rhetorical framing of my other comment, I wasn't trying to put words in their mouth, I was pointing out a predicate that they did not address.