Showing me 3 runs when I've got about 540 timeslips that say it is an old wives tale, not to mention the experience of all the guys I go to the track with, is not going to do much to change the facts.
The only time it holds true is when comparing a bogged run to a run with wheelspin. Clean run vs wheelspin, you're going to trap higher on average with the clean runs. Ask anyone with extensive drag racing experience.
Trap speed is a result of average acceleration over a given distance, since distance is the constant in drag racing. If you accelerate at X rate for 1320 feet, you're going to be going faster at the end than you would be if you accelerate at X rate for only say 1260 feet (such as if you are spinning your tires for the first 60' of the run, during which time you are accelerating at some slower rate). Physics and experience both say it it's an old wives tale.