[DatSOOKin]

I am definitely in the minority here- and I will most likely get trampled for this- but other than the guy probably being an inexperienced outdoors man I don't see how this is such an outrage. I'm not going to pretend like I am an expert in the outdoors or anything of the sort, but I did go moose hunting with family last winter and witnessed first hand how insanely big and powerful these animals are.
I agree he was an idiot for approaching the moose in the first place instead of waiting it out, but I think that is likely due to inexperience. With so many animals we are taught not to back down or else we look like prey; maybe this guy grouped the moose into that predator category subconsciously due to its sheer size. Obviously a moose isn't a predator and doesn't have those same instincts, but some people with limited experience in the outdoors may revert to the simplistic outdoor knowledge most of us are taught.
To me, it looks like following the initial charge/kicking (which I'm very surprised didn't knock him over, one of those kicks to the right spot of the head without a helmet could easily kill) the moose is starting to leave until the guy cocks his gun. The moment the moose heard that sound, its stance turned aggressive again - and that clicking sound is very similar to what moose make when they are in the rut and smack their antlers against branches as a challenge (I don't know if this is relate-able as it's a different time of year but just a potential reason the moose turned back).
The man started shooting the moment it started to turn to charge again, which I don't blame him for - it is extremely surprising to me how quickly the moose went down considering it was a handgun. They are known to be extremely tough SOB's. My brother that I was moose hunting with placed his shot, out of a 7mm rifle, perfectly through the heart and lungs, and the moose was still able to run 150-200 yards before collapsing. If this moose reached the rider a second time his life could have ended with one swift kick.
*Edit - It also appears to me that the first shot it placed above the moose as a warning shot - hard to tell with the camera angle but I could be wrong.
And as to him racing past after, he may of thought the moose was only stunned for a moment and would get back up and be even more pissed off. I would hope he went back shortly after and made sure it was put down properly and didn't suffer longer (which he may of done and just wasn't shown in the video).
As for the meat 'going to waste,' this is the wild - meat does not go to waste here. There are plenty of animals that would take advantage of the opportunity for an easy feast like wolves, cougars, wolverines, coyotes, etc.
I definitely don't get the sense that the rider was just doing this whole thing for the camera. Maybe that's just me though.