I am probably what would be considered a bleeding heart liberal in parts of the USA, but am actually fairly right wing by UK standards.
This set of personal beliefs probably influences why I like some horse trainers and not others. I can't help it, it is in my cultural upbringing. Maybe that is why I like the approach of Pat Parelli, but whilst I acknowledge her great achievements did not click so well with Stacey Westfalls approach (I watch her World Champ ride on YouTube for inspiration often). I am NOT demeaning her training style at all, it is just that for my personal psyche it does not work as well.
When people are evaluating what program to follow this is an important consideration. They are going to be taking part and listening to many hours of instruction in that program and if it jars against their personal belief set it will hinder the learning process.
Also I accept that Pat is not the best rider in the world, but then I doubt that Tiger Woods coach is the best golfer in the world. If he was he would supplant Tiger Woods ! It is not necessary to seek out the best rider, but the trainer from whom you can personally gain the most benefit.
I fly gliders at an international level but my sports psychologist trainer has never sat in a glider, let alone flown one. Yet I still trust her to be part of my training team and have learnt many things of use from her.