Symlink can not be immutable - bug or feature ?

[Khimenko Victor]

[root@khim test]# touch a
[root@khim test]# ln -s a b
[root@khim test]# mkdir c
[root@khim test]# mknod d c 1 1
[root@khim test]# mkfifo e
[root@khim test]# chattr +i *
chattr: Inappropriate ioctl for device while reading flags on d
chattr: Invalid argument while reading flags on e
[root@khim test]# lsattr -d *
----i--- a
----i--- b
----i--- c
lsattr: Inappropriate ioctl for device While reading flags on d
lsattr: Invalid argument While reading flags on e
[root@khim test]# rm a
rm: remove write-protected file `a'? y
rm: cannot unlink `a': Operation not permitted
[root@khim test]# rm b
rm: remove `b'? y
[root@khim test]# rmdir c
rmdir: c: Operation not permitted