This is a sadly misinformed article. Twain’s ranking is ridiculous and could best be characterized as an example of the wry satire for which he is known. A simple reading of any serious Anglican, Catholic or Orthodox work on Mariology would address all of the mischaracterizations in the article.
It is unfortunate that the author based all of his arguments on flawed assumptions.
It's funny that the natural response of many of the Catholics on this thread is not to stop for one minute, and really think about it - really question why so many fellow Christians (because we are fellow Christians whether or not you want to believe it) see such a problem here (hint: look at Twain's list) believe this about the Church, but to instead launch a full frontal.