A political system, although composed only of interacting individuals, can have properties and produce consequences of which those individuals may not be aware and cannot control.
For instance if I along with 100 other people form a crowd, just because we are all engaged in activities at the same time and place, there may be an accident.
Someone falls over and is badly injured. The injury can be attributed to the presence of the crowd even though it may be that no individual can be held responsible. Indeed, no individual in their rush and hurry may even be aware that there has been an accident in which someone has been badly injured.
The same goes on a large scale for social systems such as capitalism. The actions of interacting individuals can have properties and produce consequences of which those individuals may not be aware and cannot control.
In light of this one can quite properly blame a social system in the sense of attributing harmful consequences to it, without blaming all or perhaps any of the individuals of which it is composed.
Ned Block, 'An Argument for Holism', Proceedings of the Aristotelian Society, New Series, Vol. 95 (1995), pp. 151-169.
J. N. Mohanty, 'Intentionality, Causality and Holism', Synthese, Vol. 61, No. 1, The Intentionality of Mind, Part I (Oct., 1984), pp. 17-33.
Elliott Sober,'Holism, Individualism, and the Units of Selection', PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association,
Vol. 1980, Volume Two: Symposia and Invited Papers (1980), pp. 93-121.