You shipped a package from your personal possession, or ordered something to be shipped elsewhere?
Anyhow, shipping isn't done by means of a person reading the package and tossing it into the proper bin. Machines read the envelope, and if it can be scanned, it likely gets shipped with as little human investigation as possible.
Could have been an error that was caught later.
Or, could have been the fastest route. Nothing is "go here from here, straightest line is best", otherwise, a lot of deliveries would actually take longer. Where the bulk can travel fastest, it goes. Looks like the PA facility was probably a major facility that moves a lot of mail together to large/popular destinations by air. More cost effective and keeps everyone happy by making delivery as fast as possible for as many parcels as possible.
Effective transit for bulk delivery doesn't always appear logical when analyzed, but take into account how much mail moves from place to place, how much comes from any particular place and how much goes to specific places. Place of origin can be anywhere, place of destination can be very common. Collect all parcels from their origins in as few nearby facilities as possible, make as few trips as possible.
Actually makes sense.
From a driving perspective, it seems like a terrible idea to go hundreds of miles east to turn around and drive hundreds of miles west from the origin, YET... parcel delivery serves people spanning 50 states, and your package moved 1 state east to deliver to essentially one state west.
What, you want personal delivery, taking your package, and maybe a handful of others from that day, destined for Chicago or nearby areas to make the shortest transit possible?
Welcome to incredibly expensive, and often slower, service.
What can Brown do for you? (and even they are guilty, but often to a lesser extent in reality)
USPS is as efficient as it possibly can be. Their services are insanely complicated if analyzed but it just works.
Package took what... 2, 3 days?
Unless you paid for 1, or paid for 2 and got 4... I see nothing to complain about. Cheapest service available and almost always faster than every other service, but they aren't always the best choice, or even possible, depending on the specifics of the shipment.