You seem to not understand what Capitalism is.
Capitalism doesn't simply mean "markets."
Capitalism is a Mode of Production by which individual Capital Owners buy and sell Capital, with which they pay wage laborers to use said Capital to produce Commodities in an M-C-M' circuit, where M is a money supply, C is the commodity produced using M money, and M' is the greater sum of Money.
The federal government being twisted by Capitalists that have grown to excessively large statuses with dragon hoards of their own in order to protect their interests is 100% the result of Capitalism.
The corruption absolutely is due to Capitalism, and to pretend it isn't is intentional blindness.