Zerbisias attributed the quotes as what is being said on web logs and web forums. His attributions were correct. He never attributed the quotes to any particular individuals, and I don't think he made an error at all, much less an error as horrible as you suggest.
Well, it's true that Zerbisias said that the statement appeared "on usefulwork.com," and that, literally, it did, though as a comment. But to say that something appeared "on" a blog is pretty obviously attribution to the blog's author, in my opinion. You could say that, literally, that's not necessarily the case and that everything in the comments is "on" the blog, but that kind of attribution is only fair if it's fair to attribute things said in letters to the editor to the newspapers they appear in. (Er, and I think Zerbisias is a she.)