I still don't see what the fuss is all about.
I don't agree with what Blizzard is doing either, and it is wrong, but it's not illegal. By installing the game you are agreeing to their EULA, which states that third party programs are cause for a ban. If you don't like that then you have to boycott the game and not play it.
On the other hand, this is extremely unfair to all the buyers of the game who enjoy cheating in single player. Even with achievements (which grant absolutely nothing besides bragging rights) I don't see how it affects any aspect on multi-player.
I don't agree with Blizzards choice on this, but really, what can we do? People have already bought the game, and I'm sure this won't constitute all of the players to get a refund.