I'm not the anon you're arguing with.
But if you imagine a simple physics scenario, a 2 dimensional box with 2 wheel, and you want to accelerate it, then it doesn't matter where the weight is located.
Accelerating the whole system is the same if the wheels way 95kg and the box 5kg, or the reverse.
This myth comes from the fact that accelerating a flywheel does require energy input proportional to the mass of the flywheel.
But the flywheels in this case are part of the bicycle, which is still being accelerated as an engine.
In any case, all that lighter wheels does is reduce the total mass in your system. That's it. Acceleration doesn't change at all for two systems of the same mass.
Usually what people are noticing with lighter wheels is a mixture of:
Stiffness - Lighter wheels tend to be better built and have less flex, running higher tensions with straight pull spokes.
Damping differences - Lower spoke counts, even with higher tensions and a stiffer overall wheel, usually absorb a little more of the road buzz, making the bike feel smoother.
Gyroscopic effects of flinging the bike around - This is pretty self-explanatory. What you *can* measurably feel with lighter wheels is that the bike itself feels lighter because the stabilizing effect of a freewheel is reduced in proportion to weight, and it's noticeable.