Because, really: by any standard of sentient-species morality and/or ethics nature is just plain awful.
Mind you, this guy is (reluctantly) calling BS on the XKCD strip in question. He says that the strip anthropomorphizes science, instead; and as God is my witness I didn’t see that until after I wrote the title to my post.
Moe Lane
Personally, I love the category that guy used for that blogpost: “Somebody Is Wrong On The Internet”.