The reason for this isn't security-related, if you've followed the steps above and have applied them to root. The reason to not allow root login is so that eac

The reason for this isn't security-related, if you've followed the steps above and have applied them to root. The reason to not allow root login is so that each of multiple administrators must login using their username and then become root or use sudo. That way if you look to see who did what, you get a username rather than "root did that". Which, of course, you usually need root to do things that end up being checked into.