The account given by the boarder as to what he said to the skier doesn't strike me as being particularly offensive. I also wonder if there is more to the conversation than was reported.
Riders in the chairs behind probably weren't looking directly at the incident when it happened, but probably saw the falling body after he went out of the chair. The lift operator has to make sure the current chair unloads safely before turning attention to the next chair. When the incident occurred, relative to unloading of the chair ahead, is unclear, but the operator at least must have seen the boarder lying in the snow and stopped the lift because of that. He may not have directly witnessed the event either. There was supposed to be another rider on the chair at the time. They need to find that person too, but if he/she was a friend of the pusher, it won't help much.
If someone fell out of a chair I was riding in, after getting off I'd tell someone and then try to go down and assist them if possible. That the skier didn't do that suggests the boarder's story has some validity.