No, that is how "true believers and zealots" are actually like. Sunk cost is a bitch, especially when you build an entire argument around a conclusion first ... then work your way back to support it with "evidence". Like zealots like Quintus clearly had.

With arguments that start at their conclusion, the conclusion "can never be wrong", just the facts supporting that conclusion can be. So all contradicting Quintus would have likely resulted in a prolonged bad-faith debate where he'd increasingly become defensive ... then likely lash out against the Twins when pushed to hard. While he backpeddled constantly to new supporting "evidence" to defend his faulty conclusion, as you easily tear through wall after wall of shitty "supporting evidence". Because attacking his ideology would be seen as an attack against him, because he's invested so much of himself into that ideology for so much of his life. He can't back down.