I joined a hacked server unknowingly and I really want to reset my stats. How do I do that?

Into your in-game console:

/resetstats

... or something similar.

And, hm... where'd you need a BUTTON for this? And why would it be on the FORUM?

If there would be one, wouldn't that also reset your other games' stats...?

Forum? No... that's just lame. But as a separate tool? That is possible... just got to wait. What you can do now is, rename your account to something like Sulpan-Old then re-register with Sulpan and it will work. Because you're using a new GUID to load your stats.