It’s because Capitalism is the nonexistent boogeyman used by eastern dictatorships to describe nations they didn’t like. If you get into what different people think capitalism is then you end up with a no true scottsman problem, if the definition is to broad then it also describes the “communisms” but if it’s too narrow then there are much better terms to use for each hyper specific case such as Liberalism, Libertarianism, Market System, Oligopoly, Plutocracy, or Laissez Faire Capitalism.