IR--No, certainly not I, claimed that a central bank, "in and of itself" makes a government fascist. But central banking is certainly an important aspect of a fascist (corporatist) economic system.
I would dispute the assertion that central banking is legal, under the Constitution. The Constitution allows the central government to "coin" (not print) money. It does not give the central government the power to establish a de facto monopoly in banking (or any other form of commerce).