What you say seems to go hand in hand with the article's conclusion.
It seems quite reasonable that if you are able to easily see concrete examples of statements for those (and only those) where others can do so as well, then this would indicate a general alignment with the wider society and also be correlated with prosocial behavior.
In essence, if you're given a subjective, metaphorical task where the "correct answers" aren't entirely logical, then this enables evaluation if your subjectivity and your metaphors are aligned with the social consensus or not. As this task is very easy for some people and not so for others, then this seems informative about some objective property or ability of the test takers, even if "bullshit-sensitivity" IMHO isn't a very accurate name for that property; there are some people for which statement #2 is clearly not bullshit and there are some people for which it's debatable, and without labelling one group as correct or wrong, it illustrates a difference between two different groups of people.
It seems quite reasonable that if you are able to easily see concrete examples of statements for those (and only those) where others can do so as well, then this would indicate a general alignment with the wider society and also be correlated with prosocial behavior.
In essence, if you're given a subjective, metaphorical task where the "correct answers" aren't entirely logical, then this enables evaluation if your subjectivity and your metaphors are aligned with the social consensus or not. As this task is very easy for some people and not so for others, then this seems informative about some objective property or ability of the test takers, even if "bullshit-sensitivity" IMHO isn't a very accurate name for that property; there are some people for which statement #2 is clearly not bullshit and there are some people for which it's debatable, and without labelling one group as correct or wrong, it illustrates a difference between two different groups of people.