That's not exactly a compelling argument. More importantly, you're conflating a lot of things here and consequently misstating what was said. What med students/residents/attendings on SDN often state is that you should not make school decisions based upon match lists. To suggest that there are no difference between schools is excessive. However, whether those differences matter is up to the applicant--do you care about research? location? cost? interdisciplinary resources? flexibility? curriculum? Don't choose based on match lists, which require knowledge about student-scenarios that you don't have. Choose based on these, which are all very important reasons to consider a school and are considerably more interpretable for applicants.
As far as the "value added" of schools--if it exists, I don't think it necessarily reveals itself in terms of the match list. There have been many posters who attended these schools who have basically said as much. The reasons aren't new, they're not surprising, and they're fairly obvious. A match list is just a document of where people went. It doesn't tell you where they wanted to go (is this actually their top choice? did they want to specialize but didn't have the application for it?), what they did to get there (did they do anything "special" that other students at other schools couldn't have done?), or what they did after (did they go into Medicine to specialize or because they actually liked IM). I love my school, I think it's the best medical school, I'm sure our match list looks fine, but I also think the success of the students is mostly because these guys are crazy talented and hard working. Hell I'm just trying to keep up, it's a pleasure to be around them.