Absolute nonsense. Anyone who knows anything about Nietzsche knows that Darwin affected him negatively as Nietzsche hated that thought that man was NOT special.
"But Darwin's specific contribution to the theory of evolution influenced him [Nietzsche] only in the negative sense - he denied the validity of 'natural selection' and a 'struggle for life' - and Darwin was in any case too recent to constitute part of his 'tradition'."
FROM: Nietzsche by RJ Hollingdale. 1973, Routledge & Kegan Paul Ltd.
The power and consequences of ideas is an underlying message of the essay. Notice that the author never said nor implied in any way that Nietzsche committed the exterminations. The slaughter was left to Nietzsches adherents.