In MacOS, the reported disk usage for a directory is sometimes reported as zero e.g.
$ du /etc
0 /etc
But, how is it possible to store any directory content without any blocks?
Check if /etc is an actual directory or symbolic link.
ls -al /etc
Demo:
renegade@Renegade:~$ du test
28 test
renegade@Renegade:~$ ln -s test my_link_test
renegade@Renegade:~$ du my_link_test
0 my_link_test
renegade@Renegade:~$ ls -ltr my_link_test
lrwxrwxrwx 1 renegade renegade 4 Mar 12 06:56 my_link_test -> test
renegade@Renegade:~$