This long dead, poor horse deserves a funeral and final resting place. You are absolutely correct, "Pushing the "Pile" is NOT a foul. Unfortunately that was NOT what was being discussed. However, "Aiding the runner" is a foul, as described in NFHS 9-1.
As some would suggest, a somewhat innocuous foul, that was suggested might be avoided (without being ignored) by considering that the runner's OWN forward progress had been stopped, when the "aiding" began, and therefore happened AFTER the play had stopped.
Or, of course you could decide to consider the "aiding" occurred during the play, and identify the foul. One of the many split second decisions you'll be challenged to make during a game.