It can easily be both. He was not a good coach, but McDermott has not been a good coach, either. The main point the source was making was how McD never takes accountability so he predicted if things unraveled, instead of taking accountability for his own mistakes by recognizing them and growing as a coach, he would axe Dorsey.
It turned out Dorsey probably should have been let go, but at the same time, the fact is McD has had gaffes this season (and in past ones) just as bad as Dorsey. History shows throughout the numerous sources cited in the article how McDermott never takes accountability for his own mistakes. He's not taking any accountability this year, either.