Not so fast there. circuit comes to Ben's defense, kinda.
If my understanding is correct, a point that circuit makes is that a natural rate rate of interest, like potential output, is a theoretical term that is model-determined rather than being an observable. Consequently, it may be useful for a central bank to use a model in which a natural rate of interest at full employment figures in theorizing about monetary policy.
After all, if a central bank is going to set monetary policy through the nominal interest rate, then it has to have some rationale for doing so, and for economists, that means having a model. Since exogenous money has been discredited that leaves the central with with the interest rate as its policy tool. So the question becomes how and when to use that tool.
However, Ben doesn't seem to imply that he thinks there is actually a Wicksellian rate that leads naturally to full employment equilibrium in the long run if market forces are left to operate. What would be the point of monetary policy in that case unless to influence the short term. But that is basically to dismiss the long run as realistically significant.
Or maybe he does "believe in" an actual Wicksellian rate that naturally leads to full employment in the long run but concludes that doing nothing and waiting for "the long run" is just not practical politically and that monetary policy can fill in.
Fictional Reserve Barking
circuit