In my experience, people who say this seldom have much experience with animals.
I happen to live, partly by choice and partly by sheer laziness, in an exceedingly blue-collar, lower-class neighborhood. I will occasionally refer to one of the alcoholic, druggie, foul-mouthed neighbors as an "animal." My wife always reminds me, quite accurately, that this is an insult to animals.
Humans as a "superior life form," except in the obvious way of intellect, strikes me as a complete absurdity. "Higher" in undeniable ways, but scarcely superior. Hence the need for the Christian explanation of a fallen humanity, a fallen creation, and a susceptibility to supernaturally intelligent demonic forces. The Christian explanation scarcely focuses on why the cockroach or duck-billed platypus kingdom is such an evil, disgusting spectacle but rather on why the human one is.