The rm command refuses to delete the directory by the '.' name. If you instead use the full path name it should delete the directory recursively.
It is also possible to delete the directory if it is the current directory.
[testuser@testhost] /tmp$ mkdir ff
[testuser@testhost] /tmp$ cd ff
[testuser@testhost] /tmp/ff$ touch a b c
[testuser@testhost] /tmp/ff$ rm -rf ./
rm: cannot remove directory: ‘./’
[testuser@testhost] /tmp/ff$ ls
a b c
[testuser@testhost] /tmp/ff$ rm -rf /tmp/ff
[testuser@testhost] /tmp/ff$ ls
[testuser@testhost] /tmp/ff$ ls ../ff
ls: cannot access ../ff: No such file or directory
[testuser@testhost] /tmp/ff$ cd ..
[testuser@testhost] /tmp$ ls ff
ls: cannot access ff: No such file or directory
From info rm:
Any attempt to remove a file whose last file name component is .'
or..' is rejected without any prompting.