Because those are DMs. There has to be an outlet to appeal a ban in case it was in error. The strange thing is that mod mail becomes the banned person’s last channel of expression at GAW. The mod mail from common trolls is probably uninspired, predictable, and boring, but the mail from decent users who didn’t expect or maybe deserve the ban might be more thoughtful and enlightening. Maybe the mods get lonely sometimes so they ban decent people frivolously to start a conversation.