I've read that article before, or one like it. I don't think race mixing is unhealthy , there's no evidence to support it. It might even be a little bit healthier than monoracial breeding.
Don't really care. They still get the same rights as me, and they should be allowed to love who they want to. Who cares if they mix?
Mixing genes is fine. Fusing a strong culture with a weak culture ends up with the stronger culture becoming weaker.