We mostly just ban people who show complete lack of any kind of ability to learn. People who keep insisting on something that got them banned. For instance, one of the legitimate permabans currently issued is to a person who, despite dozens upon dozens of warning and long talks from staff, keeps registering alt accounts and harassing artists, and then has the audacity to call everyone who accepts commission “a thief” and claims that everyone must draw for free for him because “this is a show about friendship and magic” and “you must respect its values or else…”