There's a certain kind of leftist who thinks "negotiation" is a magic spell. If you're really good at it, and say the right words, then the other side will just go "yes, that sounds reasonable". In reality, negotiation is about finding an agremeent that *both* parties prefer over no agreement.
These aren't the main points but having been a diplomat: a) Diplomats don't scale in effectiveness with numbers. Who do you think the 43rd member of your delegation is going to be negotiating with, the hotel concierge? b) "Figure out how to negotiate" is really insulting to some talented people.