I would actually argue that the worst of the TSA fuckery has more to do with the systemic attitude of the organization from the top down, not just individual bad training. A single airport having issues = bad training. Every single airport in the US having issues = an authoritarian system that discourages independent thought and problem-solving, does not allow for individual discretion and humanity, views its mandate as a form of punishing people, treats everyone it comes into contact with as a criminal, and values obedience over intelligence.

Some of that is inherent in the TSA mandate. Most of it is due to bad management, unclear mandate, the human tendency to run with any small amount of authority until it's a huge amount of assumed authority, an internal culture framing everyone but them as the enemy and them as the noble valiant defenders of freedom, and an organizational culture that rewards bad behavior rather than disciplining it. Power-tripping agents are able to be power-tripping agents because the system was designed to back them up and reinforce their power-tripping ways the whole way.

The TSA is optimized for desensitizing agents to the humanity of passengers, and that is never a good thing.