In my experience people provide excuses because they're being addressed by management in a way that is unnecessarily negative and/or management is wanting to find "guilty people" and not work out which is the best person for the job of fixing things.

That the article is clearly refusing to even mention this casts a big shadow over the rest of its conclusions. Some of the other things are the result of personality (like taking credit or sloppiness) but making excuses is 100% context and a defensive coping strategy literally every time I have seen or done it.