I hear you. For me, I don’t think I try to rationalize it. It seems straightforward to me. The schools think admitting legacies is better for them do it (see USC and Stanford thumbing their noses at state money and public opinion), and those that don’t drop it. Is it unfair? Obviously. Is it what I would choose if I ran a private school? No. But, I really don’t care if a private university decides it is worth it to them. Public universities it’s a no for me though
For the record, I am one of the mythical black alums often discussed in these topics, and have a h.s. senior who is a double legacy at a school that still does legacy and she is not applying there because it is not the right place for her. I have no self interest in legacy staying.