Chick, I love this post! I think everyone is guilty of being a "purist" occasionally. I, like you, have found that I seem to hold tighter when some other purist comes gallivanting around spouting questionable opinions as undeniable facts LOL. That's why I usually try to keep my posts open by using the phrases "some horses", "many riders", "often", and "occasionally". That way, I can still get my point across, but without sounding like some fanatical nutjob that goes around screaming "this is always right", "that's never wrong", "this always works", "that never fails", etc.
Generally speaking, I think pretty much everyone has their "go-to" methods that they are most comfortable with so those are the methods that they try first. The difference between a bad horseman and a good horseman is what they do when it becomes obvious that those methods aren't working. So many people just get frustrated and end up trying the exact same methods...only more forcefully, which definitely doesn't work.
IMHO, one of the marks of a good horseman is someone who can effortlessly switch and integrate countless different methods into one that will work for that particular horse. Some of those clinician methods can work great, if you get the right kind of horse, but they are still cookie cutter methods and if you happen to want to try a different shape, then they either just don't do it or their other DVD costs megabucks.
Heck, in my pasture, I have 2 different horses that require 2 completely different methods of handling/training. Rafe, I have to push and demand. If I don't, he gets pushy and demanding himself. On the opposite end of the spectrum is Pokey, I can't push him at all. If I were to try, he would hurt either himself or, more likely, me...not out of malice, but out of fear. If one of those cookie cutter people tried to handle either of them the wrong way, they would have a "dangerous" horse on their hands very quickly.