"Average expected contribution" is not precisely defined in the Harvard document you provide, and thus does not commit Harvard to any particular course of action.
Also per that NYT article on wealth at colleges ~15% of Harvard frosh come from the top 1%, so that's a decent chunk of the remaining 45% that clearly don't need aid and likely did not even apply for any.
I doubt you will find many people out there that feel they paid too much for Harvard. Certainly there are bigger fish to fry as far as college tuition rip offs.