I agree that postmodernism, or at least your definition of it, is so much nonsense (in the realm of hard sciences, at least - soft science unfortunately does suffer from human contextual bias issues).
I don't read SciAm (maybe that's an issue), but I'm a bit suspicious that this could be a political hit piece.
That being said, if any of the claims in the article are true (e.g. calling statistic normal distribution curves an affront to humanity), that would indeed be a travesty (that such makes it through editing).
I think a less impassioned, more objective take would also present e.g. the number of times a needlessly conservatively minded piece made it through editing.
I.e. is it that SciAm is suddenly biased unscientific drivel or is it that society representatively has become more extreme?