A320,
Everyone but you on this thread confirms that the radalt will be accurate in this case because the plane is not tilted, is not closing too rapidly with the terrain and, close to impact, is not passing over significant buildings or steeply sloping ground. It was also proved reliable by checking every landing on the FDR file, and found to give -6 feet in every case while taxiing.
When you deal effectively with this, that the radalt is reliable, it will be time to discuss other matters.