You speak of "the calculus of a responsible corporation" and "the job of government" as if unrelated phenomena. The latter authors the corporate law that sets the former. And it would take an extreme case indeed for a company's directors or employees to violate a fiduciary duty by implementing a diversity hiring initiative. Even if there were a plausible argument that a given initiative "cost" the company relative to other hiring practices, there will almost always be plausible arguments why incurring the "cost" is in the company's best long-term interests, all things considered, in which case courts will defer to business judgment.