but how does it get lift if it is prevented from accelerating from 0 to 1 km/h of ground speed
That’s the thing - it is not prevented from accelerating. The wheels are functionally frictionless. That’s why planes have brakes. The plane pushes on the air to move, & the treadmill could accelerate backwards until the plane’s tires explode.
Some people seem to define themselves by the things they don’t like. That kind of negativity is worth working on to push out of your life, for your own happiness.