species inbreeding and recessive trait selection are different things.
If you judge people based on the color of their eyes or hair, I guess you can't understand it. But color isn't definiton of species. Mammals have fur color grey and brown, because it gives them advantage in survival by making them blend with harsh environment. Brown haired people and browne eye people don't get raped as often. (peer-reviewed, probably)
Blonde person who is very blonde who looks different from everyone else will be treated differently. Especially among males, who will be harsh towards ESL gods. So it comes to the fact that it isn't on happening, but Recessive traits are CHOSEN by organism because they serve less value in survival.
On the other hand, interbreeding between species doesn't define recessive or dominant or explain the proportions. Interbreeding is realized by fertility of the offspring. The lower fertility the more there is difference between species.