When configuring an Ethernet interface for a static IP address the dialog will 
not accept the data unless a DNS server address and a default gateway address 
are specified.

Obviously if there is more than one Ethernet interface on the system then you 
do not want to have a default gateway for each one.  But even if you have only 
a single interface then a gateway might not be desired.  There is no 
requirement that a network have a router.  Small networks that are all on a 
single subnet without Internet access are reasonably common.

Having the number of DNS servers exactly match the number of Ethernet 
interfaces is a bug in the kickstart configuration file format.  Having 
multiple DNS servers when you only have a single Ethernet device is common, as 
is having multiple Ethernet interfaces and only a single DNS server.