Alright guys, calm down.
There was a good article on why P* guns are perceived as hitting harder in one of the Airsoft magazines, I'll see if I can find it but it was along the lines that due to the way they work HPA users tend to use heavier ammo which through the joy of conservation of momentum has more of the kinetic energy it's imparted with still left when it makes contact. Thing is though it's STILL only 1J (especially at the Mall due to their strict FPS enforcement).
Generally I don't have an issue with anyone using an HPA gun. If they want to lug a tank of air along with everything else then hey, that's their problem. The one in use at the Mall however is set up with a ROF like a sewing machine and THAT I do have an issue with. But then I have an issue with that regardless of the gun or how it's powered.