Universities were heavily involved in the creation of the internet/ARPANET, and IIRC, the University of Utah was the third host on the internet (in 1969 or 1970), so the list probably just omits the non-dot-com domain names.
None, of course, will appear before the domain system was setup. These are for TLDs only. Arpanet came before, as well as other competing networking systems, and it was only the transition to a domain system that this history makes sense. See RFC 799 written in September 1981.