What does your quote have to do with anything, and what does selective breeding -- practiced for thousands of years -- have to do with the fact that variations are selected in nature without human intervention?
human intervention according to nazi rational is completely natural, thus nazi selection was completely natural....ie natural selection.
eugenics, genocide, reguardless of human technology,(no less natural in theory than a stick weilding chimp) by nazi definition would be natural selection.
do you agree that human are special, not merely just another animal?