I know people often struggle with reading comprehension. For that, I have patience/compassion.
But "ignore my non-negotiable thing you don't like, while discussing other terms and negotiating a deal on false premises" happens too often to be a reading problem.
My theory is it's a shady negotiation tactic. They think if they can get me SO invested in the idea of their $200 invoice, I'll change my mind rather than blow up the deal.
Friends, they are wrong about that. Wrong-wrong-WRONGITY-wrong.