Obvously, you are running Oracle Spatial, MDSYS.USER_SDO_GEOM_METADATA is the view, MDSYS in Oracle SPatial is like SYS and SYSTEM so you should not touch this schema at all. Look at the view below created by MDSYS.

SELECT SDO_TABLE_NAME TABLE_NAME,
SDO_COLUMN_NAME COLUMN_NAME,
SDO_DIMINFO DIMINFO,
SDO_SRID SRID
FROM SDO_GEOM_METADATA_TABLE,
(select username from user_users)
WHERE sdo_owner = username


basically, noone can see the metadata except the SDO_OWNER(owner), nothing wrong with this at all.