Heinlein wrote "honorifics and formal politeness". I interpret this as things like saying "please", "thank you", and other straightforward ritualistic decorative words - not as actually changing what you're actually saying to avoid hurting feelings.
There's a big difference between reformatting the message and changing the message.
What's described in the comment I responded to is exactly "reformatting the message" - you still communicate the same thing, ultimately, just in a way that allows the person on the receiving end to save face.
And of course, things like this only erode language semantics over time by making more and more words and phrases seem sarcastic; we have "/s" but there is no reliable marker of non-sarcasm (cf Poe's Law).
There's a big difference between reformatting the message and changing the message.