Here we go again!
All I can't say is that neither you nor the person who posted the video, have ever ridden a horse that 'takes a hold' when going into amjump, so following hounds, racing or eventing. You might well make the bland statement that it is a lack of training, that in many cases is not true, you cannot say that top competition horses are not trained and schooled.
The pictures that were at the end of the video were extremes, the girl who aftermher barely run was socking the horse in the mouth, should have been reported and disqualified.
This has all been talked about before and those starting the thread are usually not very experienced or well versed in true horsemanship.