Many creatures are bred for colors. Conformation and genetics are far from the only thing people breed for, and I'm honestly one to support color breeding. If color breeding didn't exist, a lot of exciting colors wouldn't exist in the world of horses. As others have said, I'm sure she's already considered other things of her mare, and what does it matter, since it sounds as though she plans to keep the foal.
If you're not worried about breed, see about joining her up with a colored breed with strong color genes.