I'd think that depends on the model of responsibility at play.

For example, suppose I hire a building contractor to build a house, and the electrician he subcontracts makes mistake.

From my perspective, the prime contractor is equally responsible for that mistake regardless of whether he used a subcontractor, or did the work himself but used a broken tool.

This doesn't make the electrician any less of a "person" in the deeply important ways, but it's not a distinction that's relevant to my handling of the problem.