Protocols are about consensus, almost by definition. In computer protocols, we get the consensus before we start using the protocol. In social interactions, we're molding the protocol as we use it.
As for communicating "correctly", it's a matter of (mostly) definitions and circumstances whether putting people off and "correct" communication are consistent. You may have transmitted the correct information to someone's brain, but not annoying people is usually an important goal, sometimes even more important than that of transmitting the information. Maintaining someone's good opinion of you might outweigh the importance of whatever info you want to tell them.
You can't communicate effectively without a protocol/language/etc, but communicating is not about consensus; it's about communicating ideas/thoughts/etc. Consensus is a part of communication, not its aim.
I agree that not offending/annoying someone is beneficial and might outweigh the message you have to communicate, but that isn't relevant to discussion about the efficiency of the protocol. If in spite of brusqueness, your point comes across, then it's effective communication.
Think of the "consensus" as the embedded state within a communication.
In a feudal society a lord might send a written missive to the King or Queen, and if they did it would contain a ton of horribly polite boilerplate, because the consensus of the time on both sides was that anything less was disrespectful.
It is very possible that your lack of words in a given communication sends a point across that you never intended, even if the point you had in mind also made it across.
In computer protocols, we get the consensus before we start using the protocol.
VSRP analogue in computing: Unannounced, start omitting headers in response to HTTP requests. They are unnecessary baggage that gets in the way of the actual content of the message.
Not quite. If you're using VSRE, the information contained in those headers is already implicit. I can't think of an example off the top of my head, but I'm sure there are protocols where you don't need to send loquacious headers or equivalent with every response. "VSRE" says, "go ahead and assume I know what the headers would be and skip them". If you're not expecting headers, it's not a problem if they're missing.
As for communicating "correctly", it's a matter of (mostly) definitions and circumstances whether putting people off and "correct" communication are consistent. You may have transmitted the correct information to someone's brain, but not annoying people is usually an important goal, sometimes even more important than that of transmitting the information. Maintaining someone's good opinion of you might outweigh the importance of whatever info you want to tell them.