Why are people so angry? It was a mistake, it was corrected. Part of the explanation may be the extremely partisan times we live in. For all the good things it has brought our society, the Web has also fostered ideological hermits, who only talk to folks who believe exactly what they do. This creates an echo chamber that only further convinces people that they are right, and everyone else is not only wrong, but an idiot or worse. So when an incident like this one arises, it's not enough to point out an error; they must prove that the error had nefarious origins. In some places on the Web, everything happens on a grassy knoll.
Background -- Jim Brady runs the "Post.blog" weblog on WashingtonPost.com which was the scene of a maelstrom that erupted over a inaccurate article written by Deborah Howell involving Jack Abramoff... That article was inaccurate, but it lead to becoming proof by many that the Washington Post is colluding with the Republican Party in deceiving the public, and so on, and when the Brady shut down comments, it proved the Post hates the blogosphere, are tools for the administration and many other ridiculous thoughts. Funny as when the Post prints an article bad for the administration, the same actors will add the piece to their arsenal, while not conceding that such behavior would be bad for a party organ. Likewise, actors on the other side behave in exactly the same way.
That said, I disagree with the belief that this is a function of increased political partisanship, as similar reactions can be see in many other fields. Just ask anyone who writes something disparaging about Apple, or the Macintosh.
I'd like to expand on this later...