I think it means whatever someone meant, but often that isn’t elaborated, so often I don’t really know.
I think sometimes they mean that we benefit from imperialism, while other times they mean that we’re jointly and severally guilty of it and/or responsible for it.
I think that many—perhaps most—people think in a moral framework, while others don’t.
I’d say that most of us benefit from it and ought to struggle against it, but I wouldn’t say that each and every one of us is “guilty” of it. Bourgeois democracy is a dictatorship of the bourgeoisie. Not every Russian peasant was guilty of the Tsarist empire’s crimes.
The reparations question I feel is above my pay grade, and the answers probably depend on the material conditions post-dissolution/revolution, and I can’t see that far ahead.