Lets consider two possibilities.
a) The author wishes to induce an emotional reaction in his readers to demonstrate this effect. In that case, he should attack taboos on both sides of the political aisle, in an effort to maximize the number of readers having an emotional reaction.
b) The author wishes to intellectually discuss some psychological findings. In that case, he could simply focus on a few small obscure groups with irrational beliefs (e.g., 9/11 truthers, UFO abductees) in order to minimize the number of readers who react emotionally.
I can't figure out what purpose he is serving by exposing only half his readers to the negative emotional reaction, while exposing the other half to the positive emotional reaction that comes from criticizing their political opponents and affirming their already held beliefs. (Unless of course the latter reaction is what he is going for.)
It seems the point of the article was that this issue is a spectrum issue and can trip up folks who may otherwise believe themselves to be approaching something scientifically but in fact have been pre-biased by their emotions on the issue. At least for me (and I do consider myself open minded) it was useful to think about the mechanism behind the 'irrational' response, which certainly could help me in influencing change in organizations where such change would be emotionally difficult.
"I can't figure out what purpose he is serving by exposing only half his readers to the negative emotional reaction, while exposing the other half to the positive emotional reaction that comes from criticizing their political opponents and affirming their already held beliefs. (Unless of course the latter reaction is what he is going for.)"
Perhaps he was going for people to step back and say "Hmm, I'm responding emotionally, let me compare that emotion to whether or not I think his point valid, and how my emotions influenced that thinking." Sort of a step outside your own complexes kind of thing.
Your criticism here sounds like you feel that he didn't "attack ... both sides" fairly enough, so either he should have picked more examples that you already agree with, or consider irrational.
There are some who would say that the 9/11 "truthers" are no more irrational than anthropogenic global warming "skeptics", so why pick one versus the other?
...That said, I agree that 9/11 conspiracy theorists would have been a good example to include, mostly because of the strength of their convictions relative to the really thin evidence available.
I think "out of their way" is a stretch, but, of course it did. It had to present the topic in a way that would be compelling to readers. If you think anthropogenic global warming is bunkem, then the use of terms like "denier" is going to be a trigger for you. If you think that vaccines cause autism, then you'll find similar terminology, and have a similar trigger.
Regardless of the issue or which side of the issue that you're on, if you had an emotional reaction to the article, then that mostly just proved it right on the actual subject that it was talking about: that people react emotionally, not logically, when their convictions are confronted.