Thanks for the comment, Kris.
I don’t think the confusion is about the preference, but about what is meant by the term irrational.
Sometimes it’s used to mean ‘stupid’ or ‘unreasonable’ – less kind versions of ‘against one’s self-interest’. In order to do so correctly, we really have to know the person’s preferences, and indeed how they trade off for example short term interest versus long term interest. Is a smoker irrational for prioritizing the immediate pleasure of a nicotine fix over the long term risk of cancer or cardiovascular conditions?
Sometimes it’s used to mean ‘not reasoned’ – behaviour with origins in biases or heuristics, rather than in conscious deliberation. Preferences don’t really play a role here, and it would be incorrect to assume behaviour reveals them.
And there are nuances and variants: acting on an unquestioned belief, acting on a subset of the available data (perhaps conditioned by confirmation bias).
That doesn’t mean that preferences don’t pose their own problems. It’s far from clear that we have stable and consistent preferences, even if we account for context.