The primary reason is over RP dialogue. I like to give my characters a little life by doing light RP (No heavy or ERP, just giving my character a little personality). And although it's not really my style of roleplay, folks could roleplay as someone edgy, broody, or even critical of other in-game races like that fellow in the Archers guild, Silvairre. In addition to that, some guild themes like a little conflict to advance a goal or something like that (RP wise). My concern is that certain tones of RP could actually get someone in trouble, or be used to get one in trouble. The broody guy that imitates the personality of Squall gets banned/muted for a short while because he's "toxic", the lalafel that's critical of those "knife eared bastards" is banned for hate speech, and because Vavil had at outburst that someone in his group lost the Mcguffen (more toxic/aggressive behavior).
it seems extremely frightening that the broody character saying "I hope you all die, slowly" could land him a ban. It'd be boring to meet people with a personality like Vavs all the time.
