It seems to me that the GCA profession, and the mode of criticism and how criticism finds an avenue of public discussion has been an evolving process.
As we noted above, the old timers often made critical comments of other archie's work. They seem to have had more writing talent and wit, but none-the-less, they took their critical shots. Then, along came the ASGCA, and the desire to put the whole profession on a recognized national platform to function as a guild. The fledgling new ASGCA found it practical to have a code of ethics that restricted negativity, for the obvious reason that they didn't want to undercut their mission with the vehicle of criticism, leading to squabbling among its members. That all seems to have worked out well. The criticism of various archies work seemed to be left to the writers, non-ASGCA members. I don't doubt that some ASGCA members may have from time to time primed some writer's pumps to draw critical reviews of competition out in the open. But, they could fall back on their code of ethics and take the high road.
Then, some young turk named Doak, passionate but not very worldly at a certain young age in his 20 somethings turned a bunch of the old standards upside down. He as a young archie, recently student, wrote "the" book. It seems he pissed off a lot of the old guard that got comfortable with the "code".
But, what is most important is that "the" book was a jumping off point for challenge of the professional GCAs to raise the bar, as noted above. Even more writers became more critical.
Now, we have younger GCAs like Ian asking if the standard of critical comment should be less restrictive. Politely, it is suggested that positive criticism and polite words of critical analysis might be considered as good for the profession. In a way, that seems to come full circle to the old days when witty or clever criticism was placed in a writing or quote of the old masters, when commenting about others.
Art, even science needs very critical analysis by the professionals and artists in the field to advance their subject, IMHO. The people that do the work or create the art need to speak up. The writers are OK, but the practicing professionals are the ones that should take the podium and say things when they see things have gone in the wrong direction, perhaps led by any particular other practioner of that field.
The fine line seems to be the need to keep the petty squabbling down to a minimum, with critical analysis for the betterment of the art and craft of GCA. I suspect we'll keep evolving along that line, never quite reaching the ideal balance.