I will keep my anaswer short. First, the primary mission of Postfix is to deliver mail, not to force someone into adopting a particular world view. I have asked Viktor what patch would restore interoperability.
Second, we have to be mindful that Postfix and Exim are not the
only MTAs in existence. If placating Exim results in the loss of
interoperability with other MTAs, then we may have to reconsider
our approach.
Wietse
