I'm not on a Fedora machine at this moment, but doesn't yum have a --nodeps option. (Take a quick glance at its man page.)
If not, just use
rpm -e --nodeps Postgre
Removing it won't break bind.
Sometimes, the removing of dependencies can be a little surprising--I never do yum -y remove anything since the day I removed wireless tools and it took out a bunch of KDE programs that I needed.