Superusers are always exempt from lowly permission checks. The documentation:
A database superuser bypasses all permission checks, except the right
to log in. This is a dangerous privilege and should not be used carelessly; ...
To see whether your current user is a superuser:
To list all superuser roles:
SELECT rolname FROM pg_roles WHERE rolsuper;
And the schema owner can do it, too. The documentation for
Only the table owner, the schema owner, and superuser can drop a table.
To list schema-owners:
SELECT n.nspname AS schema_name, pg_get_userbyid(n.nspowner) AS owner
FROM pg_namespace n
WHERE n.nspname NOT LIKE 'pg_%'
AND n.nspname <> 'information_schema'
ORDER BY 1;
About the same as
\dn in psql.
And who are you?
SELECT current_user, session_user;