The problem starts with the belief in simplifications that in no way reflect reality. "True capitalism" doesn't exist, can never exist, and is as undesirable as the plague. The connection with "free markets" is a feat of propaganda. This idea that socialism has no "free markets" is proof of the propaganda's success. Economies depend on markets. The capitalist idea of organisation is an anathema to free markets. While socialism is the closest one can get to a functioning "free market" system.
Getting back to farming subsidies, and subsidies in general. The issue is the distortions introduced through lobbyists and corporate machinations. The provision of subsidies is not governed by the question "what is best for the population?" Rather, it is about staying in power, serving clients, not people.
Exposing the false labels handed out. Folks are accused of being liberal, while they're nowhere close to the middle of the spectrum.