guess the hog did not stop and read that he was located in communist china where the state has made it very clear this is not allowed. Even has many laws to that effect.
Honestly though even a knife would not have done any good for those people other than to further enrage the animal. They would have done much better to have lit some cloth on fire and on the end of that broom and chased it. That would have likely ended it but people do not think that way when adrenaline hits unless they have been trained/taught to.
The issue being it does not look like any of them had the attitude/determination or knew anything about how to kill a hog with a knife or really what to do. Looked about the same as it would have played out in any big city here in the US were guns are severely restricted and they usually would not have allowed any good sized knife either. Not to mention most mid to well off city folk these days are passive weenies.
If they would use dogs for guard animals instead of eating them they also might have done ok.
You really do have to have experience killing hogs with a knife to be able to do it effectively in a stress situation like that. Got to know to grab the rear leg with a death grip and knee behind the shoulder to flip it down. Bury the blade behind the forerib section about a hand behind the shoulder and pull/slice down hard will usually split the heart and fillet a good amount of lung as well. Its over in a few seconds after that.