I don’t know much about nazis but I thought an important part of their rhetoric was to draw distinctions between types of human.
So they’d not see “10bn humans”, they’d see maybe 100m aryan and 9.9bn “untermensch”; the latter being equivalent to rats available to be experimented on.
I just find rats to be much more preferable, pleasant and considerate creatures than humans. I see humans as a single tier of unterratten; totally different hierarchcy.
Not if they’ve pre-tested on non-volunteers though.