I think the article nailed it in that most programmers think they aren't any good because they have no clue where to start. With no training and a non-obvious technique (and perhaps some intimidation at trying and failing), programmers just say "I can't do it."

I would bet most programmers could do an OK job at designing things (at least, not painful :). But great design is still talent that has to be worked at, and I think it is hard for anybody to get to that point without devoting him/herself to it (and probably having innate talent as well).