The user evaluates the skill of a craftsman but his peers evaluate the craftsman's integrity. Fellow members of a craft have to be the ones who police their profession. These are the equity courts that govern a profession or trade. This is the genius, for example, of the scientific community.
When ideology overwhelms a profession's ability to police the conduct of some of its own members it throws into doubt the society's authority, and the society's ability to engender good leadership weakens.