Most everyone thinks of noon in terms of solar noon - they just don't know it. Solar noon is when the sun is at it's highest point in the sky for a given location. So their point was that noon would no longer be aligned with that intuition.
Solar noon is an outdated concept that is completely meaningless to the vast majority of the modern world. There's no reason we should tie our modern workday to solar noon any more than we should tie our software launches to the lunar cycle or our bathing schedule to the tides.
people aren't robots. having lunch outside on a warm day feels good.