I was talking about astronauts in low earth orbit

Bill - a little bit further down in Vernon's referenced page, objects visible from low earth orbit are also discussed. The key point, as repeated in the article you reference, is that this does not distinguish the Great Wall from a great many other man-made objects, including the Kennedy Space Center, the Golden Gate Bridge (your article), and if we're talking ancient objects, the Great Pyramid, for instance.

I, for one, had always taken it as read that the Great Wall was the only man-made object visible from space. You implied that it was at least something worthy of note. And we were hardly alone with our misconception:
http://www.bugbog.com/ancientsites/world_wonders_by_month/world_wonders_july.html

It also struck me that the myth of the Great Wall being uniquely visible from space (originally "from the moon") originated well before it was possible to establish the fact (1930s). That sense of having been hoodwinked for a large part of my life isn't entirely appreciated, but I suppose I ought to get used to it.