You can't actually but SCII, you can only lease it. If you lease a car and alter it they will also probably take some sort of punitive action against you. Blizz is 100% within their rights on this, the only debate is if they should or not.

You can say achievements mean nothing because a lot come through just playing the single player game, but quite a few are very challenging. Blizzard is interested in preserving their integrity. Would I care? No, but if they think it is important it is their community to cultivate.

Also we are only hearing one side of the story. From a few years in WoW I heard similar sob stories after every wave of bans, and by and large they were people talking out of their asses who got pissy for being banned for cheating.

Using hacks to see the story
Completely unfounded as the game comes with built in cheats