> So then why didn't the editors suggest it for a more appropriate journal rather than call it unpublishable entirely?
Because knowledge of out-of-domain journals to which an out-of-domain paper might be appropriate is neither the role nor general competency of a journal's editors (OTOH, general familiarity with the published work in the area in which you are attempting to publish, which necessarily includes some familiarity with the venues in which works in that field are published, is part of the role and presumed competency of a researcher in any field.)
I'm not suggesting they should have said, "Resubmit this to the International Journal of Experimental Sociology." Just "Hey, this is more of a question for sociologists; maybe try that kind of journal."
Much like how Sokal criticized Social Text for not recognizing when something was a question for physicists.
Why should they have to give less direct feedback or make suggestions like that? To avoid hurting his feelings? To point him in the right direction so he knows what to do next? The author is a tenured university professor, not some high school student.
Why do you say less direct? The impression I get from the article is that none of the article actually gave a specific reason why the paper was not appropriate for the journal.
Did you know Sokal submitted his paper to several journals before getting accepted? And that he rewrote it to make it appeal to what he thought the editors would want to read? The paper wasn't even peer reviewed, so the fact that it was published is not significant at all, even though I found the discussion interesting and justified. I just think that the deception he used was not warranted and only served to generate attention and sensation.
Because knowledge of out-of-domain journals to which an out-of-domain paper might be appropriate is neither the role nor general competency of a journal's editors (OTOH, general familiarity with the published work in the area in which you are attempting to publish, which necessarily includes some familiarity with the venues in which works in that field are published, is part of the role and presumed competency of a researcher in any field.)