In particular, I’ve noticed how the pro-capitalist people don’t seem to realize that we’re not living in a pure capitalist system. Instead we’re living in a mixed economy where key elements are socialist: road building, firefighting, postal services, food and drug safety testing, old age pensions, even ambulances (except for one minor exception).
A 100% socialist (a.k.a. communist) system might not be possible (at least not yet) due to human nature. The few times that it has been tried, at least in theory, it has quickly become an authoritarian system instead. But, AFAIK, it’s so obvious that 100% capitalist would fail completely that no society has even bothered to try it. Hundreds of years ago there were brief experiments with things like capitalist fire services, and Pinkertons as police, but they failed so spectacularly that nobody even thinks of going back.
So, instead we quibble about “capitalist” vs “socialist” when we’re really just arguing about whether the mix should be 80% capitalist, 20% socialist or 60% capitalist, 40% socialist.