That doesn't really follow. We don't need to have a complete map genotype to phenotype in order to have an understanding of the weight of genetic component of certain traits. Just because we don't know exactly which genes cause a certain hair color doesn't mean we can't guess which parents are more likely to have children with that hair color. The same goes for behavior that can be measured and predicted. As long as that prediction is more accurate than a random guess, the prediction has value.