CrossFit Trainer Certification, 2007 (Wikimedia Commons)
The CrossFit video shows horrible weight lifting technique. The Coach Hatch video has great technique.
Bad technique is just one reason CrossFit is bad.
CrossFit does not allow anyone to start off at a beginners level. The workout of the day does not give lighter loads or easier exercises for beginners. A good strength and conditioning program should allow the person to start light until their body gets accustomed to the training program. Only then can the body handle a more intense workout. Increasing the intensity and load in a periodized way is used by most collegiate and professional sports teams. It allows the body time to adapt to the stresses of training.
There is always a spike in injuries when a group starts to participate in CrossFit. Read this interview with Marine Capt Brian Chontosh. Capt Chontosh said there was a temporary spike in minor injuries at the outset, but he was soon able to move from injury prevention to injury avoidance through increased work capacity.
If these Marines were allowed to start at a lighter intensity and weight there would have not been a spike in injuries. If you overload the body too quickly you will get injured. The proper way would be to slowly and steadily increase the load and intensity of the exercise.