Why would Fedex do this?

They might be sending your package to a common hub.. Not necessary to the closest one. Even modern computers can’t get deliveries perfectly to the shortage routes. They might have the wrong zip/postal code.

Because that’s how their routing system works. Everything, no matter the origin and destination, gets routed through regional hubs.

The same reason UPS drivers don’t make left turns. They are instructed to only make right-hand turns. They’ve calculated that even if it occasionally increases delivery time, the math shows that averaged overall, it greatly improves delivery times. While your particular package may make this system slightly less efficient, a hub-and-spoke delivery system is far more efficient overall.

Same reason if you mail an envelope (to your neighbor) by dropping it the mailbox in your neighborhood; that envelope goes to a regional mail distribution center first. They put a cancel mark on it, read the address and route it back to your neighbor.

Everything at FedEx goes through Memphis. That is their World Hub, handling 1.5 million items each night. They don’t do any sorting prior to Memphis because that would be a waste of time.