Well, you should have just stated that in the first place instead of name calling and acting immature. A simple "we have suspended his account while we carry out further investigations, this is practice" would have gone a long way to ease people's minds and kind of reactions you got. Instead, Github just came across as massive douches.

EDIT: On second thoughts, I think I am being overly critical on all parties. Instead, I think I hands up "we messed up, but we are learning" approach would be better, and we see how both sides act if/when this happens again, lessons learnt and all that!