You're right, but you may want to consider that highly monotone communicators may not actually notice most of the non-literal signals that get passed in typical social situations.

Models be built from something, something related to the modeler's interpretation of their own interface into reality.

That said, it's nice that such a model was made; it's a nice reference / jumping off point. Someone more sensitive to their percepts and the nuances of life would be hard pressed to formalize any model at all; they'd be hard pressed to unfocus from the complexities and responsibilities of social life to do the abstract work of modeling.