[Gnump3d-users] Is port 80 a security issue when root?

[linuxhippy]

I want to run my gnump3d server on the typical port 80 so that my users don't 
need to type in ports and some firewalls don't block access to my server.  I've 
been running it in Slackware Linux for about 2 years now.  I changed 
/etc/gnump3d/gnump3d.conf so that port is 80 but saw the comment in there that 
the user has to be root to run on port 80.  Why?  Is running the server as root 
with a command line only interface and iptables firewall a security issue?

Marty