I'm not defending the hackers if they violated any laws. At the same time, its Blizzard/Activision's fault for tying the game into their stupid Battle.net system.
Believe it or not, I've have NEVER played a Blizzard game over Battle.Net regularly (I played an open DiabloII game for like 15 minutes once, lost a bunch of ears). I don't give a rats ass about my ranking or anyone else's. I just want to be able to play the game at a leisurely pace, and sometimes that means cheating.
I even wrote my own local-character hacker for Diablo II, it would only up stats and grant skills, and un-kill Hardcore characters. I was never able to create items. Point is, it was a fun exercise in hex-editing and programming, plus the ability to one-hit kill almost every MOB was cool too. I'd hate to think Blizzard would sue me if I could even try to do the same on Diablo III (for Starcraft, the in-game cheats were sufficient for my needs, and I assume Starcraft II has similar cheats?). But then again, with the mandatory tie-in to Battle.Net, I haven't even bothered buying Starcraft II and probably won't buy Diablo III.