It's hard to escape the impression that some of those insisting on "professional behavior" are looking for a way to exclude those who they deem not qualified, so as to get out of the way of the Big Corporations who want IETF to do what they want it to do.
While I understand the allure of conspiracy theories, it is far more straightforward and far more accurate to assume that those insisting on "professional behaviour" are simply looking to exclude "unprofessional behaviour" wherever that is found, with no ulterior motive.
Anyway, if "unprofessional behavior" is not defined, those in power can use any deviation from "normal" as an excuse to sanction participants.
And the same lack of definition allows those not in power to claim that they were not behaving unprofessionally and any sanctions against them were therefore an abuse of power.
FWIW I like the list you posted in an attempt to define professional, though I personally would add a lot more to it.