All life's plenitude is worthy of life

The scientists of era of Modernity (1870s-1960s) believed that Darwin's evolution would be best served by Man giving Natural Selection a leg up - by Mankind draining the gene pool for humans and non-humans alike.

Cue Auschwitz and Aktion T4 and cue today's ever more rapid extinction of all species other than our own.

Those scientists were dead wrong - it was just bad science.