Why doesn't this surprise me?One individual stated that it should not have been possible for the user to make that mistake because the rebreather should have been designed so that the incorrect fitting would not match. It would be a simple design change. He was nearly alone in that view, though, with his words drowned out by the majority repeating the phrase "user error!" over and over and over and over and over. The "change the system" guy kept repeating it, and everyone else got frustrated. Eventually the guy calling for that simple change in the rebreather's design was banned because he kept persisting, to the annoyance of others.
I hope Gareth Lock continues to make progress to chance dive culture. Sure people do stupid things from time to time (daily for me), but no one intends to do so especially when there are dangerous consequences potentially. I personally believe that if a system can be configured incorrectly, training is only part of the solution. System design changes go hand in hand. Incidents will never be eliminated but processes and systems should always be open to enhancement.
You related a story of Bill Hogarth continuing to improve his dive configuration. Some are obstinate to change unfortunately.