I think legacies offer an important benefit to the school–a generational tie between families that adds some continuity, stability and narrative over time. Returning to an example from a previous discussion,
I know a family who had grandparents who went to Tufts, mom and dad went to Tufts and the son went to Tufts but the daughter didn’t get in and ended up at University of Virginia instead. If she had gone to Tufts, there’s an elegant generational story for the family and the school.
I won’t bother to address the “dumb sons of the rich” argument as academic research referenced earlier in the thread shows that the legacy kids are often better prepared and are, arguably, more academically qualified than many of the first generation kids. For the kids pushing this, their logic has a fundamental flaw as they presumedly think “if only there wasn’t a legacy tip, more people like me would be here.” I’d suggest doing a quick gedankenexperiment where legacy preferences have been entirely removed. Would a university’s demographics significantly change? Smart money’s on they wouldn’t which just means that the university lost something while gaining nothing.
Note: other than finding this topic fascinating, this isn’t self-interested as there’s no way I’m trying to convince fragbot jr. to apply to my alma mater as I don’t think it’s worth the money.