It's the reason why vehicles have a separate "city" and a "highway" fuel economy rating, since the former takes into account the expected stopping and starting you do in city traffic which you would not on an uncongested highway. It also makes intuitive sense if you understand physics: in a non-hybrid ICE vehicle, you impart energy from the engine into the wheels to accelerate the vehicle and you impart energy from the wheels into the brakes to decelerate, effectively wasting the original energy from the engine as heat. In hybrids and EVs some of that energy can be recovered by using the motor as a generator to recapture it in a useful form.
Wouldn't it be more-so that with ICE vehicles you loose 100% of the kinetic energy as heat when stopping. With an EV you convert a portion back to the battery packs with regenerative breaking.
Correct, though many times costs are not just fuel - total ROI includes service cost, availability of replacement parts, insurance costs, etc - a NG car could cost more in fuel and still be cheaper for effectively forever depending on how the books land.
Not trying to be rude, but it's because it's intro Physics (F=m*a, with F coming from fuel, battery, or brakes), with an understanding that the process that generated that force has an efficiency that's less than 100%, mixed with a dash of intro Calculus (integral of force).