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Description of problem:
From host.conf man page:-

       multi  Valid values are on and off.  If set to on, the resolv+ library will  return all  valid addresses for a host that appears in the /etc/hosts file, instead of only the first.  This is off by default, as it may  cause  a  substantial performance loss at sites with large hosts files.

From RHEL 6+ that the "multi on" is set in /etc/host.conf

# cat /etc/host.conf 
multi on

cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 6.4 (Santiago)

Same behaviour is not observed in RHEL 5+

Is the default set wrongly, or just incorrectly documented?

glibc does not set or own /etc/host.conf, it only reads it.  Assigning to the right component.

Intentional ... but performance hit is not occuring anymore - see https://bugzilla.redhat.com/show_bug.cgi?id=486461#c2 for reasoning. I recommend to change the man page instead.

Created attachment 913738 [details]
host.conf.5 multi on by default

Created attachment 913986 [details]
host.conf.5 multi on by default

Created attachment 914073 [details]
host.conf.5 multi on by default

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2014-1382.html