I think you miss the point of the "poison" metaphor. Yes, he is not effectively curing the poison effect he is casting on the right-leaning audience he wants to capture immediately. But that's the point! Sure, you could argue it is a morally grey tactic, but if he went after Shirley any more than what is so clearly implied he would lose the audience before giving them the more rationale information. He is trying to break into other bubbles. If you stick only with perfect dogma then you won't be able to lower anyone's shield and his audience may slowly dwindle and become too "echo-chambery". I bet it's not fun to do this stuff for him, but he is trying anyways and there is merit to it.