i think it is an analogy that is useful in elucidating what people view as the morally relevant aspect.
i don’t think it makes a ton of sense to me that the encryption or lack thereof is the relevant factor - if we think that proprietors of unencrypted messaging should be required to turn over chat logs, then encrypted messaging should probably be illegal or we have left a massive loophole in.
the scale being the relevant issue is another thing as well. i worry that if you somehow create a protocol for dencentralized messaging, you somehow then become liable for misuse of what could have been an academic project, etc.