For example you may be able to convince someone who believes that ufos are spaceships that while that maybe the case its not proven and while its ok to believe thats a possibilty to not declare it to be the truth and keep an open but skeptical mind, once they get into the whole reptilian shapeshifter territory its a safe bet youre bot going to make any headway. When confronted with a teabagger youll be able to figure out fairly quickly whether or not theyll actually listen to your points or if theyre completely closed off to new info.
As it was said in the thread about vegetarians, the problem arises when a person's belief becomes their identity. Attacking the belief is inherently a personal attack, because without the belief they are nothing. It's also why it leads so directly to ad-hominem attacks in defense. They don't comprehend any logical difference between me telling a Teabagger that Obama is actually a fairly average president, and him telling me I'm a socialist scumbag who needs to move to Iran so I can live in a godless dystopia where welfare-dependent women have abortions just to make baby Jesus cry.
Their arguments are absurd, because they are completely devoid of a logical basis. But just try telling them
that. No, they think they're making all the sense in the world, because, well, they just are and that's how God intended it to be, so there. There is no such thing as "open to new info." New Info itself is the exact thing they are opposed to, often explicitly. UFO nuts might tell you they understand that not all UFOs are alien space ships, they might even actually understand that. But they won't believe
it. They won't stop thinking they are alien space ships
. As long as you allow for the possibility that they are right, they will interpret it as a guarantee that they are right. And if you don't allow for the possibility, then you're just a close-minded drone who believes everything NASA tells you. And they'll take that
as evidence that somebody important is trying to stop them from believing "The Truth."
It isn't a question of "how crazy are these people?" It's a question of "how can we make them stop breathing oxygen on my planet faster?"