And he can think whatever the fuck he wants about that, which is entirely my point, because he, as a theoretically sentient being, is aware that he is flawed.

Unless there's a character driven reason not to! Arrogance, naivete, backstory, whatever.

But, more pressingly, my point is to make you aware that there are more options available to the system for Deception checks than pure statblock measuring! And every table should be aware of that!

As well as the fact that Persuasion and Deception are not mind control.

Which I'm still not convinced you are, because this argument is still going.