Possibly because it was written 5 years ago? Hard to be relevant and accurate with an article that is so old now. Personally I'd agree with most of it still really. I remember reading this when it was first written!
I think that many of points in that list don't make you a bad designer, as they have their place within typography.
For example the double line space (see what I've just done there) between paragraphs. Using them is perfectly acceptable, in fact if you didn't use them, long passages of text would become difficult to read. It's actually a lack of attention to detail that's the problem.