I think you misunderstood the "auto doors" option. Such option doesn't even exists. There's a GSX "auto mode" option, which will just call all GSX services in a sequence, but it won't touch the doors.
The reference to doors next to it, is to control whether GSX will wait for YOU to open doors while in auto mode. If it's enabled, GSX will not care about the doors status and will proceed with services without interruption, even if doors are closed. But, it will still NOT TOUCH THE DOORS.
GSX never operates the doors for you, we leave this task to the user OR to the airplane developers, who know better than GSX could ever do how and when it's safe to close the doors without disrupting their simulation.