I'm not questioning your ability/technique but wondering what the basis for the above statement is. I looked at your Smugmug gallery with the failed shots and it's clear that a good number have missed critical focus. If you're panning and keeping the focus point on the same part of the subject then there's little or no prediction required (based on the shots in the gallery, not all situations) as the change in distance to the subject is minimal. A bike heading towards you, or very obliquely across you, has a reasonable rate of change of distance but that's not happening with your failures.
Bob
Seeing that im not fully side on for a pan or inside a corner the distance to subject still is changing all be it not as much as head on so would expect the cameras A/F to pick this up and adjust not only for the fact that it will recognize that the camera is being panned but also via its own calculations will register the subject distance has itself changed from one frame to the next.
The size of subject from first image to last image in the wheelie shots changes showing that there must also be a change in distance from camera to subject and this can easily be seen in the images without the use of a distance measurement being given and infact regardles of panning skill you can see the front focus shift through prediction on the floor in all shots including the crash sequence where it shifts onto the curb.
The last set are at a very high shutter speed of 1/2000 sec so as to eliminate comments of motion blur from poor panning technique.
This is a quote from the Canon A/F guide all be it for the 1DX as its the closest system i believe to the 7D MKII but i will try and find one specific to the 7D MKII.
With a predictive AF system the camera is continuously recording the position of the subject and predicting where it will be for the next frame based on its motion so far. If the camera fails to detect the subject position in one recording period, the AI Servo AF III algorithm will ignore the negative result and the next focus point is based on the previous accurate results. Equally, the EOS-1D X will ignore the results when the AF distance appears to jump greatly so that it can continue to track a subject even if an obstacle passes between you and your subject. Equally, if there is suddenly a large jump in the focus distance, the camera will not drive the lens to the new distance directly. Instead it will gradually drive the lens focus, based on the previous successful focus distance results.
The increased sensitivity of the focus system has also allowed for faster predictive focus measurements. In previous EOS cameras there was a warm-up period while the AF system began tracking. This has now been reduced so that the EOS-1D X can begin predictive tracking as soon as a subject begins to move.
The complete article can be found here
http://cpn.canon-europe.com/content/education/infobank/autofocus/autofocus.do
After 6 years of covering motorsport i know for a fact its not user error i can assure you.