Capital has always been formed by exploitation - you cannot have a surplus without paying workers less than they create, it’s an accounting relationship.

That said, the amount of income disparity in “communist” countries has generally been much less than capitalist ones.

As far as oppression, it depends how you define that. But if you want to look at the amount of incarceration (a good measure), the US not only is greater than any socialist nation’s average, but even the worst of the Stalinist Great Purge. And this ignores just how cruel capitalism is in the global south to make those profits.

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