Seems he did not graps it...questions that are closed as duplicates when they are clearly not duplicates.
But, he did:
Human beings have the incredibly annoying habit of asking the same questions using completely and utterly different words. They're really good at it.
I think the main problem is that questions can be closed as duplicate without explanation. My observation has been that a lot of people do not yet know how to simplify their problems, and are thus less effective at asking questions. They may not realize that their question is actually a duplicate, because the people closing it did the simplifying for them and realized it was a duplicate.
As an example, this morning I saw a question with a subject like "Conditional += operator" -- their question was asking why something like (a + b ? c += 1 : c += 2) was resulting in an unexpected number. Any moderately experienced coder will have boiled it down to "how does the ternary operator work?", and maybe closed it as a dupe of another such question. They'd have been technically correct that it was a duplicate, and yet not helpful at all to the person asking the question.
I think the solution may be to allow a sort of "closing answer" -- something that closes as a duplicate, with a minimal explanation showing why their problem was a duplicate.
Interestingly enough, this appears to be a problem unique to the professionalish "no nonsense" standards of SO. In the days when IRC was the primary point of help, if you asked a question poorly you'd usually get a lot of equally poor mocking responses until you learned to boil it down. Condescending trolls or not, it sort of forced you to think about your problem a bit more and after a few weeks of that, you're a lot better off.