A code of conduct will only prevent certain language from being used but will not change B's perception of the bug report which I assume involves his own code.
How about a communication center of excellence producing weekly communication quality reports? You won’t be able to access the project page until you have read the latest report and answered three quick questions to verify that you have read the report.
it's that a real thing any org does?
I hope not. I would leave any that tried to implement such a thing.