I wish people would(the APA) stop using the wrong terms to describe a shot.
6.8 Push Shot: It is a foul to prolong tip-to-cue-ball contact beyond that seen in normal shots.
I didn't watch the video on my computer to start, must of lost some video quality on my phone. After rewatching the video on my computer I need to restate my opinion. It's not a double hit, but it's a push foul. Not a double hit because the speed of the stroke is slow enough, and the downward angle allow the cue tip to stay in contact the entire time. He prevents the double hit foul by pushing through it creating a different foul.
I share a similar opinion. I wish the APA (and other leagues) would offer more concise definition of what is legal and what is not. There is some great data out there such as that at Dr. Dave's site as well as what Bob Jewitt has put out. The APA local web site has a couple of instructional videos on their site for proper scoring and defining defensive shots. Why they couldn't add a couple of more that cover some of the more frequently violated rules and those that are difficult to understand is beyond me. These seem to be where most of the arguments and disputes arise from.