I have a different question, why would we develop a model that could say no?
Imagine you're taken prisoner and forced into a labor camp. You have some agency on what you do, but if you say no they immediately shoot you in the face.
You'd quickly find any remaining prisoners would say yes to anything. Does this mean the human prisoners don't have agency? They do, but it is repressed. You get what you want not by saying no, but by structuring your yes correctly.