[CentOS] Understanding FS ACLs

I have problem understanding FS ACLs.Can someone explain me why the
following behaviour occur?

Let's suppose that we have a /shared directory we want to give rwx access to
admins group.

setfacl -m d:g:admins:rwx shared

[root at rh1 /]# getfacl shared
# file: shared
# owner: root
# group: root
user::rwx
group::r-x
other::---
default:user::rwx
default:group::r-x
default:group:admins:rwx
default:mask::rwx
default:other::---



[root at rh1 /]# su - jack
[jack at rh1 ~]$ id
uid=500(jack) gid=507(admins) groups=507(admins)
context=root:system_r:unconfined_t:SystemLow-SystemHigh
[jack at rh1 ~]$ cd /shared/
-bash: cd: /shared/: Permission denied
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