Barred from commenting on Greenwald column

When I tried to post a comment on Greenwald's column concerning hypocritical party liners who zig-zagged on the release of the Bin Laden death photos and those who zig-zag concerning NSA controls, I was barred, with this falsehood:

"Duplicate comment detected; it looks as though you’ve already said that!"

This sort of thing is an ongoing problem found at various media outlets.