It’s a problematic proposition, and normally one I actually enjoy examining and unraveling. It is, of course, less amusing for those living in the moment. Meanwhile, it is very easy to see how this works:
• A does not appreciate the behavior of B.
• Behavior of B is observably a reaction to behavior of A.
• As A attempts to engage discussion of B behavior, B responds that the discussion cannot take place without consideration of A behavior.
• A walks away from the discussion.
To sum it up in a very juvenile manner, A wants to continue to offend B through recognizably offensive behavior patterns, and expects B to simply shut up and behave. That A and B are allegedly mature adults is interesting, exasperating, and probably largely irrelevant, of course, unless A wants to make this about B being childish.
We might also include or disregard, according to wont, the suggestion that it is rather quite silly, and even pathetic, that such circumstances occur so regularly in our lives.