Terrible user experience, that I can fully understand. But this is not an UA issue, simply it's not for everyone to handle end users and for those who are able, that can be hell of a sport over the years. 
For what is worth, whatever script they use, doesn't change the fact that all end users are hard to handle, everywhere in the world.

Bottom line, let say EAI is possible in Mailman (with a lot more development), but there are other circumstances why it's not and probably will not be. 
Therefore, I would say - EAI is a standard, right? So, Mailman is not fulfilling standards. Some other solution can fulfill the gap, like Dr. Ajay's...

All best, 
Dušan 



1. 1. 2025. 23:20, "John R. Levine" <johnl@iecc.com> је написао/ла:

On Wed, 1 Jan 2025, Душан Стојичевић wrote:
> Or mailman can use two email addresses per user (EAI and ASCII alias) to deliver all messages. Or, mailman can check EAI capabilities of certain email address at the registering stage,
> and forbids them to register if they are not EAI ready. Hey, now it's forbidden for EAI addresses, and no one makes a problem.

Those are certainly possibilities, but mailman doesn't do any of those.  I
can't blame them because they all have a terrible user experience.

Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly