Oddly enough, I think that both of these viewpoints work together very nicely.
Human beings are, generally speaking, irrational. We have a sort of flashlight'o'rationality that we can shine on specific things for periods of time, but most of how we behave is guided by a mixture of instinct, culture, emotion, and our life experiences.
It is pretty well-established that even highly rational people tend to choose a position and then build chains of logic to support it. As a very strong case in point, look at how the world of mathematicians worked to "correct" Marilyn vos Savant's solution to the Monty Hall problem.
And while we can work to change our habits, to instill more rational behaviors, we are still operating from within a system that is mostly irrational and emotional. And more importantly, we have to either want to change, or be made to want to change.
This is rarely accomplished by telling somebody that they are wrong.
Personally, I tend to think of human beings as being rational-at-the-core, but with that rational core being surrounded and filtered by a wall of culture, emotion, and experience.
So when people disagree with me, it is because their chain of logic is based on a different cultural-emotional-experience state than mine.
And if I can not understand where they are coming from -- listening is a superpower here -- I can not hope to either learn the thing that they know and I don't, and nor can I hope to change their minds.
Now, when it comes to arguing for a viewpoint, it is our natural instinct to defend ourselves -- a verbal challenge to what we believe is still very much an "attack".
The simplest way to bypass this reflex, is to start from a position where you are on the "same team". To agree with where they are right, and to validate the parts of their position that you share.
From there, you can then work in small steps and gentle pressure to engage both their rational core, as well as their culture-emotion-experience filter.