I went to a course on how to negotiate with people delivered by a hostage negotiator for the (British) police that basically agreed with what you say.
The key they said was to work out what the person's motivation was and then adapt your communication to suit what was appropriate.
The general rule was to (at least appear to) match the emotional intensity of the person you were talking to. If you're negotiating with someone who's ready to jump off a bridge, rational argument and NVC is not as likely to help as an emotional appeal to their underlying concerns.
It's a great balance of story-telling and teaching. He teaches some simple rules then provides examples of how he actually used to practices to get the results he wanted.
Also, none of his suggestions felt fake or pandering. Just small tweaks to how you word and approach things can have a huge impact without necessarily being an expert.
The key they said was to work out what the person's motivation was and then adapt your communication to suit what was appropriate.
The general rule was to (at least appear to) match the emotional intensity of the person you were talking to. If you're negotiating with someone who's ready to jump off a bridge, rational argument and NVC is not as likely to help as an emotional appeal to their underlying concerns.