As co-GM of that RP, going to elaborate a bit that he's refused to be cooperative when asked for elaboration, as well as shown major auteur license and obnoxiousness.

In addition, they have continued to act like a petulant child whilst accusing everyone else (who were acting as mature as possible given the situation) of being childish, as well as stating that the main site rules don't apply to them because they weren't specifically stated in the OP (despite it actually saying that the main site rules apply).