A convenient excuse? A CONVENIENT EXCUSE!?!
Let's see, off the top of my head, these are extinct species I know of: All mammuthus species, the Dodo, the Labrador Duck, countless species of Rails, New Zealand... Well, in short New Zealand's got extinction ALL up in it's shit, Giant Auks, Stella's sea cow, dinosaurs of various shapes and sizes, pterosaurs, most ancient pre-dinosaur Archosaurs, ichthyosaurs, thylacines, ammonites, terror birds, most giraffe species, mesohippus, various armored fish, freaky-ass herbivorous mammals, etc. etc. etc.
I could go on, but in short, NINETY-NINE FUCKING PERCENT OF ALL SPECIES ARE NOW EXTINCT. There is NO DENYING THIS.
If you think humans would do any better, think again! Humans are speciesist fuckers, if anything! Do you think we would just peacefully allow Australopithecines and Neanderthals and Homo Ergasters to coexist with us despite our huge physical and mental advantages over them??! Evolution, motherfucker, DO YOU KNOW IT?! Whether we intended to or not, we directly caused the extinction of ALL the other hominid species! ARRGHHH!!/rage rant