I guess the "he sucks", "he's an idiot" comments repesent people's right to an opinion, but I just doubt CBS is a dumb coach. When I start to doubt coaches decisions, I usually rest on the assumption that the coach knows his players (skills, current health, fatigue, combinations,...) a lot better than I do. Of course in a game like NBA basketball, especially when you have a team that is likely to be putting less talent on the floor than your opponent, anything can happen -- even when you put the right guys out there in the right situations.
I don't really know if Stevens' is a dumb coach or a smart one, but my guess is that he's pretty smart and will make the correct (higher percentage) decisions most of time. One thing I am sure of, he's a much smarter coach than I'd be.