Obviously it is hard to tell everything that is going on, as we are just seeing a video. However, in both cases the issue is lack of experience. They should never have been on the throttle that long. Moab has way too much traction to be able to hammer down and hold it in a stockish vehicle.
The issue is that the tires WILL hook up, and being on it that hard means that you are going to keep moving no matter what. A small bump is what was needed to get the trucks moving, but then you have to let off and slow it down. If not, you start bouncing like they did and then you have lost control of the vehicle.
Obviously this really only applies to novice drivers in full body trucks. If you drive a rock rod designed for hammer down driving, completely different rules apply.
Baby Beast 2- 1999 4Runner SR5
Baby Beast -1987 4Runner SR5-Gone, but not forgotten