This doesn't make us want you more.
You are telling me that if Braunwald calls the Dean of admissions and says, "Hey, I heard you guys are considering this student that worked with me, you should take him, I can vouch for his abilities." That is not going to make you want that student more? I understand your point that random celebrities calling on a student's behalf are useless. But, that is not what I'm talking about. I'm talking about well known PIs or physicians calling and vouching for students that they have worked with as an adjunct to their LOR or out of the blue to simply say, "If you haven't looked at this app yourself, I think that you should, this guy is special."
Admittedly, this affects very few people. And yes, most of these calls are annoying and mean next to nothing. But, many application processes are governed heavily by phone calls. In vascular surgery residency, virtually everyone gets a phone call about applicants that a program is seriously considering. I'm sure that it is the same in most if not all other competitive fields. When it comes to looking for jobs post residency, there are no LOR, it is 100% pure phone calls and who will call on your behalf. Yes, medical school admissions is fundamentally different in terms of scope and numbers compared to those two examples, but the people involved do overlap and networking/who you know will always have some impact and in a handful of cases every year a significant one (ie admission vs. no admission).
Yup. We call these people "legacies".
Nobody ever bitches about them, ever, on SDN, but God forbid a URM gets accepted with stats less than someone else.
I don't know what the common use of the term is, but at least in the circles that I have run, a legacy is someone whose family have an affiliation with a particular school. For instance, my father went to medical school, they interviewed me, more than one interviewer brought up the fact that he went there. The funnier one was when I interviewed at Hopkins, one of their interviewers brought it up and asked if I would even consider Hopkins given that my father went somewhere else. Knowing people that will call on your behalf is a little bit that, but it is also networking and also simply being a strong applicant, usually with things outside of the classroom. I've been asked a couple of times by students how to stratify their research 'credentials' and honestly, what a PI would say in a phone call is probably the most important thing for an undergrad where publications/impact are even more hit or miss than usual.
I personally have a problem with the legacy concept, it is stupid, maybe it is growing up in upper middle class north east where this was rampant and seeing students that had no business being in particular undergrads/medical schools getting in and doing poorly. But, if someone is willing to stick their neck out for a student because they think they are good, not just because they are related? I think that that is very very different.