If I am grossly negligent and strike someone with my car as a result (say, because I've been drinking) I'm responsible.
But if you're a cop you can be grossly negligent, throw an explosive (that is illegal for a citizen to possess) into a baby's crib, have it detonate and critically injure the child therein, not find the suspect or the alleged drugs you were told were supposedly there by a "confidential informant" (a claim not backed by hard evidence or truth, obviously), and not only are you not charged with felony assault and unlawful detonation of a destructive device like any ordinary person would be neither you or your agency and its government will pay for the medical bills of the baby you harmed either.