Earlier quoted context omitted.
It isn't about calling someone a moron, it is about being able to respond, "Thanks, I can be fucking stupid at times, can you show me where I am being moronic here?". It is also about being able top unguard your own language should you know that the other person is operating by the rules, not to be insulting, but so to not worry about it for that conversation and so not having to run that whole level of extra process…
But you could further optimize your communication by dropping the profanity. A listener declaring Crocker's rules says they will not be offended, but at best, profanity communicates your emotional reaction to a situation. In seeking optimal communication of information, profanity is largely wasted bandwidth.
I have certainly been in stressful situations with people where I was confident they were struggling to say what they really meant because they were angry and trying to remain civil.
Giving someone permission to vent at you, in the interest of also giving you a truth they've struggled to present politely, is one of the functions of this practice.
I think you may be taking "optimally" to mean something like "ideally"; in this context I take it to be "the best available". It would be ideal for the angry person with the important truth to find a polite way to present that truth — but with emotion involved the best available option may be to accept some profanity along with the truth, in preference to the truth being hidden behind an attempt to stay civil.