> That makes intuitive sense, since preference relations ~are~ partially ordered sets
Preference relations of rational agents are, anyway. When it comes to us mere mortals, well, see https://en.wikipedia.org/wiki/Intransitivity#Occurrences_in_....
yes of course, but even then we are left to describe such intransitivities in a useful manner rather than conclude the actors is simply non-rational.
If it were so, then human behavior would be impossible to analyze. Instead, if we focus on causes and consequences of non transitive preferences - like in behavioral economics - we may regain the ability to do analyzes.
Then, parameterizing the choice situation and / or introducing strategic dependecies between actors leads to analyzing sub/supermodular correspondences on these sets. In fact, the most general version would make use of quasi-supermodularity. I think Milgrom&Roberts 94 show that this is the most general way, one can think of coherent (rational) decision theory.