I think I read in a "big bumper book of facts" when I was a kid that while the Great Wall itself is not visible from space (and certainly not the Moon - that idea was risible even as a kid) when dust storms blow over and around it, the outline and location can be discerned. Plausible?
Anyhow, where's the calculation of the Rayleigh crtierion at 380 miles for the angle subtended at the human eye of something 6 metres wide to show whether it's resolvable or not? You'd think these people would keep their Uni lecture notes to hand of they're going to write these kind of articles. Sheesh.