> That is a smear-word created by socialists to mis-describe the "system" (which isn't a system at all) wherein people are able to freely trade with each other.
No, its not, and the “not a system” you describe is neither what we call “capitalism”, nor anything that has ever existed. Restrictions and limits on trade exist in all real-world economic systems and conditions. “Capitalism”, is, at root, a particular structure of property rights.
> So yes it is a cornerstone of socialism to falsely claim that (evil, greedy, immoral) "capitalists" exist
People who own capital exist, and I never made the moral claim that you make. (Leaving aside whether it has anything to do with socialism or not.)
> It's just an incoherent mess of ideological nonsense. It puts people into two categories, even though actually most people are in both categories
Actually, the socialist description of the structrue of capitalism does not have two categories; it recognizes a continuum of conditions, in which there are three main broad classes useful for discussion: those whose support is predominantly from renting out labor (proletariat/working class), those whose support has significant contributions from both labor and capital, as by applying their own labor to their own capital, though there are other patterns (petit bourgeois/middle class), and those whose support is predominantly through capital to which rented labor is applied (haut bourgeois/capitalist class).