I suspect Blizzard didn't ban everyone who exploited it because, well, many of the people in the 'top' clans would be gone and it would be bad press. Perhaps this is a warning of sorts and future action will be harsher? MC wasn't the brightest in promoting it on stream, so it makes sense why Blizz used him to 'set an example'. But as for the rest (like Gabynator), we now know who the 'top players' who cheated are, thanks to the rollback.
I'm glad Blizzard is finally taking at least SOME action to keep the game legit, and hopefully this opens people's eyes to what (some of) their beloved 'best' players are actually up to.
It's like any hobby/passion I guess. Some people do it to pass time, others to be on the top. Doesn't matter if it's diablo, any kind of sport, or even making a collection in some way where you are happy to get that hard to get item and "be at the top".
If you do it to have a good time, you don't care, you just have fun. Once it becomes a passion, you spend 10+ hours per day, you want to be with the best.