The concern in the example is that if the data is unencrypted then there are many untrusted middlemen that also have access to the plaintext and could use it to blackmail either/both of the trusted sender/receiver.
I agree that concern is valid (and a good reason to encrypt everything), I just think the original example doesn't really say that clearly (or at least clearly enough).
While I agree, I still feel like the original example wasn't explicit about the threat being external to the conversation. But again, that's likely me being overly pedantic/overly concrete in my thinking.
That being said, there are situations where you would want to "revoke" information you shared willingly and intentionally with someone (think in the case of a messy breakup or divorce, where that information could be socially or legally troublesome if presented in a certain way) - encryption is still weak to a "plaintext recording" attack in that case.
Anyway, again, thank you all for the informative and civil discussions X) Have a good one.
Then again, maybe I'm just being pedantic.
Thanks for the clarification - have a good one.