You write, “suppose your postmodern English professor teaches you that the famous writer Wulky Wilkinsen is actually a ‘post-utopian’. What does this mean you should expect from his books? Nothing.”
I’m sympathetic to your general argument in this article, but this particular jibe is overstating your case.
There may be nothing particularly profound in the idea of ‘post-utopianism’, but it’s not meaningless. Let me see if I can persuade you.
Utopianism is the belief that an ideal society (or at least one that’s much better than ours) can be constructed, for example by the application of a particular political ideology. It’s an idea that has been considered and criticized here on LessWrong. Utopian fiction explores this belief, often by portraying such an ideal society, or the process that leads to one. In utopian fiction one expects to see characters who are perfectible, conflicts resolved successfully or peacefully, and some kind of argument in favour of utopianism. Post-utopian fiction is written in reaction to this, from a skeptical or critical viewpoint about the perfectibility of people and the possibility of improving society. One expects to see irretrievably flawed characters, idealistic projects turn to failure, conflicts that are destructive and unresolved, portrayals of dystopian societies and argument against utopianism (not necessarily all of these at once, of course, but much more often than chance).
Literary categories are vague, of course, and one can argue about their boundaries, but they do make sense. H. G. Wells’ “A Modern Utopia” is a utopian novel, and Aldous Huxley’s “Brave New World” is post-utopian.
I think gwern is teasing us: there is no such quotation in Sluga’s Heidegger’s Crisis, or at least I cannot find it in the Google Books version. Perhaps gwern has taken the Wittgenstein/Malcolm story and swapped Britain for Germany to make a point about the universal applicability of the philosopher’s rebuke.
But for what it’s worth:
The date in the Heidegger version of the story is very suspicious: in 1939 Churchill was First Lord of the Admiralty; he did not become Prime Minister until May 1940 and it is only with hindsight that we see his significance (even in 1940 most political actors seem to have thought that Lord Halifax would be a better choice for Prime Minister than Churchill).
The version of the anecdote featuring Wittgenstein and Malcolm is backed up by a citation to Malcolm’s Ludwig Wittgenstein: A Memoir where Malcolm quotes the letter from Wittgenstein at length. Also, the 1939 date for the original quarrel about “national character” is a better fit to this story, because in 1939 no-one could doubt the significance of Hitler, and assassination attempts on Hitler were by that point a fairly regular occurrence.