A few reasons, but primarily we don't do it because our general stance is that roleplaying is a collaborative hobby. So when people partake in roleplay on Storyteller's Circle, they're doing so with other players and creating collaborative stories. Deleting someone and their content could leave large holes in someone's roleplay. It's why we have a section in our site terms when you register that touches upon this "You are granting us with a non-exclusive, permanent, irrevocable, unlimited license to use, publish, or re-publish your Content in connection with the Service. You retain copyright over the Content." Keeps a user from getting mad, rage quiting and asking for all of their content to be deleted and subsequently damage someone's ongoing roleplay. They can leave, but the content remains.
Another major reason we don't do it is to keep user records intact. Even when people have their roleplays archived, the content still exists. Deleting a user wipes out all record of that user ever existing, which from a staff standpoint can make it hard to maintain intact records in the event of users leaving and then returning at a later date (which frequently happens on web-forums). And you can't undo deleting an account. The records are gone forever.
