Only problem with your analysis is that you fail to realize that just because someone was a bad head coach it does not mean they are also a bad coordinator. Nolan and Capers are highly respected coordinators in this league. Given your same logic the Patriots would also be a laughing stock because they too employed several of the coaches on that list as coordinators.
I don't disagree with your logic nor was mine ever that many of the coaches on that list weren't/aren't very good coordinators. However you look at it though, an inordinantly high number of those goofs were coaches for the Dolphins. Heck, Wanny was an excellent DC, Cam is still a good OC and Saban is obviously an exceptional college coach but they really sucked as head coaches for the Dolphins.