Literally the only thing that defines it is the private ownership of capital for profit. Everything else is just editorialising and that Merriam Webster quote (which is NOT taken from the definition but rather a "did you know?" box aimed at school children) is ridiculous. "Pure capitalism" is a nonsense phrase just as "pure socialism" is a nonsense phrase. Presumably in "pure socialism" no one owns their clothes or toothbrush. Perhaps not even hair or teeth or organs! Grrrr socialism bad!
This childish semantic quibbling is nonsensical. A social democracy has widespread private ownership of capital, including means of production, infrastructure etc, for profit. Saying that isnt capitalist because you found some retarded schoolchild explanation of capitalism that says the only true capitalism is a system with no police or streetlights is intellectually feeble. Engage with the ideas not semantic childishness.
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