Why are the xorg libs and server and xterm part of the base FreeBSD install, since they are not needed? Just wondering

I'm not sure why they are there either. I uninstalled them all using pkg_delete with no negative consequences.

More than likely the install which was done, was a general install which included things from the ports tree to provide a ready to use machine. Understandably, you do not need these packages, unless you install something which requires to have their libs.