I would like to hide all media uploaded by the admin.
I've found an answer to this question to be pretty close. Except that the query returns all media uploaded by a specific (current) user, instead of excluding all by a specific user.
[...] if( !current_user_can('delete_pages') ) $wp_query_obj->set('author', $current_user->id ); [...]
Q: Is it possible to modify the wp_query_obj to exclude all posts by a specific user?