First hand living experience in a communist, and then authoritarian post-communist, country.
And before you say not all communist are alike and you can't generalize… yeah no, they are quite alike and you can generalize. Anyone who lived in any of them knows exactly what guanxi and other social concepts mean, the cultures are remarkably cookie-cutter.
Americans, and people living in American colonies, also have first-hand experience with American imperialism. I'm not sure why you think your experience trounces theirs?
Because "communism" is both an economic and a political ideology, while "capitalism" is only an economic one.
And before the nitpicking starts, I'm well aware that monied interests can influence democratic politics. That does not make an economic system a political system. It would be like calling democracy an economic system.