That website was simply talking about how a pedal assist sensor will activate and what compels the controller to send signals to the motor. They misused the word "faster" in the second part of the last sentence, which causes confusion. The word "quicker" is more appropriate. Faster spinning of the pedals with force activates the motor more quickly than a slower spin. That's all. Once the motor is activated, it is up to the rider to determine how the power of the motor is to be utilized and optimized.

My comment is based on a real person (me) riding an actual ebike in a real live outdoor setting, employing the bike's shifters for the optimum obtainment of speed and the optimum way to climb hills. I have enough miles under my belt of riding my bike on all types of roads in different settings to stand by what I said.

And just to clarify the question "is assist level controlled by the crank rpms?" the simple answer is no. The assist level is controlled by the rider's selection of power level ranges available for their particular ebike. The majority of ebikes have finger activated controls on the handlebar that allow the rider to chose, at any time, the amount of power needed from the motor - anywhere from none to maximum. Usually about 4 or 5 assistance levels are offered: eco, eco +, normal, normal +, and sport. The spinning of the pedals simply tells the motor to turn itself on (unless the rider selected no assistance in which case the motor remains off). Assistance itself is activated based on the power level the rider has selected, and a motor that is on. Energy is added to each pedal stroke, but the energy doesn't increase or decrease irregardless of how fast you spin the pedals unless you select a different power level.