Right, finding a single anecdote where members of a tribe that you don't like failed is a rational way to assess the general rationality of the average member of that tribe.

Keep in mind the editors of Social Text did not believe Sokal's article was actually sound philosophy. Not understanding it, they preferred to give it the benefit of the doubt. The only thing that Sokal was able to trick them into believing was that the article was intended to be sound philosophy.