Jack , I would not have used such a strong term as betrayed but the main essence of what you said, I agree with.
A lot of this is appears to be about people own personal performing background , I have spent over 45years performing at folk festivals and clubs and so tend to be thinking about a session and audience appreciation in a particular way. each to their own
Jim Bainbridge who used to be a neigbour of mine, wrote somewhere else on this forum, that an irish musician had criticised him and called him an entertainer, Jim said at the time he was happy with that.
Playing music is about entertaining, it is for ourselves BUT also for others who are not players. that is my opinion, if you have a different opinion,that is fine, Chacun son goût