So you (tnw) posted the article without attribution, the original author sees this, he tweets about it and asks wtf and then you (tnw) fix it and then you (personally) go on a tirade about how it's how the industry works blah blah blah conveniently ignoring that he knew it was originally not attributed and you reply as if it was, now you're admitting that you did in fact post it without attribution? All you had to do was apologise when he complained to you. You were in the wrong, whether it was an accident or not isn't the issue.