I don’t think that means the developers don’t consider it important; it means that the people that want E2E aren’t necessarily in their primary audience.
The prime target of this protocol isn’t power users and developers; it’s the overwhelming majority of users that stick to siloed messaging because it’s convenient, and everyone has it. First and foremost, they need to be shown that this is more convenient, and has a larger and more accessible network.
It can’t be default because the protocol is degradable by design. I would agree that they could advocate a method to harmonize all COI-aware IMAP servers. But it’s hard to get E2E encryption in a heterogeneous, legacy environment.
The prime target of this protocol isn’t power users and developers; it’s the overwhelming majority of users that stick to siloed messaging because it’s convenient, and everyone has it. First and foremost, they need to be shown that this is more convenient, and has a larger and more accessible network.