Degenerate White behavior is mostly a consequence of our degenerate popular culture. Implementing a top-down socially conservative cultural revolution by legislating morality (e.g., censoring the entertainment industry again) would mostly fix this problem. But to the degree that degenerate behavior is genetic, then it should obviously be fixed with eugenics.
People get freaked out whenever someone mentions eugenics in a positive light, but we now have the scientific technology and know-how to implement eugenics through humane means, or will in the near future. We can use genome sequencing, genetic analysis, precision gene editing, embryo selection, contraception, early term abortion, et cetera, to create a new Master Race without having to use forced sterilization or death camps.
There's also a definite elitist element to the Alt-Right. We don't really respect the anti-intellectual "redneck" culture that has dominated the American conservative movement for decades. In fact, we find it embarrassing. We want to elevate our race genetically, economically, and culturally. Eradicating the degenerate influences that have seeped into the White race is one of our main goals.