#1 isn’t meant to _rule out_ child abuse. Perfection not being an option we have to look at incentives over the long term. Bureaucrats have no incentive to care about any particular child. In fact, state child protective services are notoriously bad at it. The state destroys the social structures of support and discipline and encourage uncivilized behavior.
#2 grand parents may not be able to “press charges” but that is hardly the only way to solve a problem. Because it is outside of a legal system doesn’t mean it violates the assumptions.