You can host your own game server in UT but you're still depending on Epic services for the server listings and license (CD key) validation.
For those the service used for searching/listing the servers is being taken down. If you know the ip address of a server you can still play.
No need to remember IP addresses, we have DNS now ;-)
You have to wonder just how little hosting a lobby server must cost a company the size of epic. Collating a list of server IPs and names seems fairly trivial.
It probably has more to do with paying someone to keep it patched and running happily.