I think one of the biggest problems that leads to coaches following such a program is that they simply don’t take the time to study/read much so they don’t have much to compare it to. That is, a new coach with very little actual experience and even less effort/time spent studying the various topics of speed development, strength development, etc. etc. might attend a Barwis clinic (or many others for that matter) become floored by the presentation and his enthusiasm and accept his concepts as THE way to achieve good results.
For those guys, they don’t know any better or at least they have very limited exposure to other programs.
For the more veteran coaches, there’s no excuse for crushing athletes. A few examples 1) they are either ignoring the vast amounts of materials available on training from good sources/following poor advice 2)must not be paying attention to the short and, more importantly, long term responses by their athletes to the programs they have subjected their athletes to.