If they try to communise the economy directly, there is an enormous body of “right wing” economic theory that can knock down their plans. So instead, they go for a two stage process. First of all, they persuade people that some Damned Thing is immoral. Then they show that the free market allows or encourages that immoral thing. Then they can say, “well, we wish we didn’t have to do this, but I’m afraid we’re going to have to intervene in that part of the economy, to stop the Damned Thing, sorry”. This leaves the free marketeer floundering around having to try to justify the continuance of the Damned Thing in the name of some nebulous “liberty”. And then they say, “so your selfish desire for “liberty” means this Damned Thing must go on?” and you lose the argument in public, because most of the audience have been persuaded that there is a moral crisis that must be addressed, and you are a heartless asshole who just doesn’t care.