ukm2clong story short dudes found out in quakelive if u force to use less populated ports on a server u save 5-15 ping
Thaaat doesn't make sense and isn't what happened in that thread.
There was a command in the original version of ql which forced the client to reconnect, and it happened to open the socket on a new ephemeral (i.e. arbitrary client-side) port due to a timing issue. They then found a way to replicate this behavior in the standalone version of ql which did not have that timing issue. This has nothing to do with the port the server is listening on (of which there is only 1). For some people, some of the time they found that changing the port their client uses would cause a small drop in latency. This is speculated to be due to some kind of port-based routing or QoS on one of the hops between the client and the server but they don't actually know.
holy shit layman's terms for my caveman brain please