That both scenes require the same exposure, regardless of the meter indication, becomes obvious from a scene that includes both a white horse and a black horse. A photographer usually can recognize the difference between a white horse and a black horse; a meter usually cannot. When metering a white horse, a photographer can apply exposure compensation so that the white horse is rendered as white.
That both scenes require identical exposure levels becomes evident from a scene that includes both a white and a black horse. A photographer typically has an easier time distinguishing between these two colors; however, a light meter often struggles with this distinction. By adjusting exposure compensation when photographing a white horse, the photographer can achieve the desired result.