No...

Going postal is what a W+M1 Pyro is all about. That's what the mailbox would reflect.

going postal means snapping and going on a violent rampage. This shows the unstable behavior of soldier and demoman characters more. Even with playstyle that doesn't work because W+M1 pyro is basically doing what a pyro is meant to do.

...

The Demoman is just drunk.

The Soldier, is nuts, yes, but he doesn't have the serial streak that the Pyro exemplifies in dropping into a group of people, setting them on fire then cleaning up. And if you really want to get fancy in the postal service, think about how he puffs, degreases and sends people flying over the map with the axetinguisher, special delivery.

Lets face it, only Pyro is crazy enough to do this and still have it make sense in a strange way.

I learned something today.

Bonk + Atomizer is amazing for pestering the enemy team, running into their base, and basically fatally splitting their attention with guerrilla tactics. That is all.

this is the guy whose the kind of nuts that involves killing "nazis" in germany several years after the war ended, oh and keeping severed heads as decorations.

I dont see how that doesn't sound like the kind of person to dress up in military gear and fire a rocket in your face because yesterday you ate his lunch
[edit]
doesn't help that the pyro is the one we know next to nothing about. All we really know is the pyro is, well an actual pyro, and enjoys air guitaring.

oh and for some reason or other owns a purse

That's not serial...

The Pyro is a stalker. That takes some serious thinking skills that the soldier is not known for.

Well, maybe not exactly a serial killer. Mass-muderer might be more of a proper term for the Soldier.

Though the Spy is the most serial killer of all of them.

You are all forgetting that pretty much everyone in tf2 is insane.

They all take pleasure from mass murder, as well as having their own brands of insanity each. Sniper is maybe an exception, as he at least sees it more as a job then anyone else in the game.

He throws jars of his own urine at people and considers it to be an effective combat technique. Even though it really is, I think that says enough about the man.

Or just how far TF2 has gotten from what it originally was. I don't know.