I'll keep this short and simple: Take away SG Medals from hackers. They make the game unfair to other users, causing them to quit both SG and the server - And users should be severely punished for that.
SG Stats becomes difficult, because of the way the database/plugin works. iirc it does all the calculating on the fly (instead of regularly in the backend and caching it) And thus it's difficult to easily change the stats that are shown. It's possible to try to negate the points by taking the total points and deducting from it an amount that puts it back to zero, and deduct that amount every time it calculates. But that's a bit messy, especially with the current stats implementation. It would make the already laggy stats page even more laggy.
Yeah, but SG medals are tied to your points. So when your points don't go away, why should your medals? How would you re-earn those medals?