You need to deny access to the directory where symlink resides.
EDIT:
When you move/rename/delete a file in Unix based operating systems, you are modifying the directory in which they are located, not the files themselves. So permissions on the file don't matter at all.
You cannot change the permissions (or attributes) of a link, trying to do so is meaningless. From the chmod man page
chmod never changes the permissions of symbolic links; the chmod system call cannot change their permissions. This is not a problem since the permissions of symbolic links are never used. However, for each symbolic link listed on the command line, chmod changes the permissions of the pointed-to file.
You need to deny access to the directory where symlink resides.
EDIT:
When you move/rename/delete a file in Unix based operating systems, you are modifying the directory in which they are located, not the files themselves. So permissions on the file don't matter at all.
You cannot change the permissions (or attributes) of a link, trying to do so is meaningless. From the chmod man page