ETA: Maybe that's one reason for this phenomenon: people trying to sound smart instead of trying to be smart.
Agree technically. Yes, that is one reason that our kind can't cooperate. Of course I would reverse the connotation that our kind makes that particular mistake more than others.
My impression is that we -- geekish people in general -- do this a lot more than others. Uttering any generalisation seems to trigger people to respond with an exception, no matter how nugatory or irrelevant.
ETA: See also Well, actually.
Link.
Given the positive reactions, I think the professor seeded them with a positive impression of the site's content.