Pretty much spot on, Dick, I think that I agree with everything you have written in the previous post. In fact, I'd like to develop what you say about the nature of criticism.
In my life as organiser and performer in folk music and - more importantly and frequently - in my decades in senior posts in special education, I worked out a thought process for dealing with comments and criticisms. I would ask myself a series of questions about each comment or criticism. They were:-

1] Can I do anything about this and still be faithful to the the aims and ethos of what I am engaged in?
2] Would it be possible to do anything about this comment or criticism within the powers that I am able to exercise?
3] Is there something ulterior behind this (or as Dick had implied, does it come from someone with an obvious agenda)?
4] Is the criticism valid?

Before taking any action, I would give myself the answer to 4] If I was sure that the answer was 'no' that would be the end of the matter.
If it was 'yes' then I would check that the answers to 1] and 2] were also 'yes'. Number 3] was always the trickiest to deal with (especially in education) and it often came down to a matter of clearly stating the reasons for my actions to line managers.

Of course, it works both ways. In my last ten years, part of my role in education was to visit schools and give them advice on their behaviour policies. I was also asked to act for a three-year period as a voluntary assessor for South-East Arts attending music concerts and projects that had ACE funding using their guidelines to assess whether the money was well spent. Before making comments or criticisms, I had to make sure that they were valid and that changes were feasible.