I'm sure it was a trained move. The body goes where the head goes. The guard had good control over the guys neck.
It looked bad, but it probably would have looked like a gentle take down if the perpetrator hadn't fought it, and the guard hadn't been forced to use a little extra english.
A couple of people around me that it was excessive violence. I kind of agree, though I do think he needed to be thrown down. The way they did it by grabbing him around the neck could have snapped his neck.