>>12538823you miss the point anon was making
there's really no a priori reason to think that gravitational charge of an object should also be its inertial mass. It's harder to move a more massive object than a less massive one with an electric field since it has more inertia, but that doesn't mean that the electric charge of an object should have anything to do with its mass. We can ask why the gravitational charge of an object is equal to its inertial mass, since (with Newtonian gravity) inertia and gravitational charge act completely separately but for some reason happen to be exactly the same, resulting in objects of different masses experiencing the exact same acceleration in the same gravitational field (compare to a proton versus a positron in the same electric field)
The answer lies in general relativity.
