Can't remove default permissions entry

On RDS (thus, no superuser) we are trying to drop a user.  The only remaining item that the user owns is an "empty"
defaultpermissions entry, but we can't seem to get rid of it so that the user can be dropped: 

I'm sure I'm missing something obvious!

Logged in as xyuser:

db=> \ddp+
                    Default access privileges
   Owner    |    Schema     |   Type   |    Access privileges
------------+---------------+----------+--------------------------
 xyuser     |               | table    |

db=> ALTER DEFAULT PRIVILEGES FOR USER xyuser REVOKE ALL ON TABLES FROM xyuser;
ALTER DEFAULT PRIVILEGES
db=> \ddp+
                    Default access privileges
   Owner    |    Schema     |   Type   |    Access privileges
------------+---------------+----------+--------------------------
 xyuser     |               | table    |

db=>

--
-- Christophe Pettus
   xof@thebuild.com