The thing that confuses me is that the second example shows a histogram of the user activity which appears to be not a normal distribution. But for pilot dimens

The thing that confuses me is that the second example shows a histogram of the user activity which appears to be not a normal distribution. But for pilot dimensions, I would expect the histogram to actually follow a normal distribution. I feel the problem (and answer) of the cockpit design is presented a bit too simplistic here.