The evidence for this scenario is clear and conclusive, backed up by multiple studies and seen across the world. The unique birds of New Zealand were doing just fine until 800 years ago, when the first Maori arrived and promptly proceeded to wipe nearly all of the flightless and many of the flighted species out. When the Europeans arrived several centuries later, they merely finished the job. The megafauna of South America, once the most biodiverse in the world, died out within centuries of humans arriving, after having endured millions of years of ecological and climatic upheavals with little to no effect. The giant lemurs and fossas of Madagascar were eradicated shortly after the arrival of the first humans 3000 years ago, and the few and tiny populations of elephant birds that had managed to cling on disappeared once again after the coming of the Europeans. Arguably most famous of all recent extinctions is that of the dodo, though what fewer people know is that the dodo shared its island home of Mauritius with a wide variety of odd and endemic species, including giant turtles and multiple other species of flightless birds, all of which were wiped out shortly after people came.
This does not seem like a complicated issue - quite the opposite in fact. Every time humans arrive on a new landmass, the result has been an immediate wave of extinctions. This is seen across the whole world, and evidence for it is ample. Surely, nobody would be naive or stubborn enough to contest this, right? As we will soon see, the bounds of human incredulity and denial are truly limitless.
Raphus cucullatus, the famous dodo. Once abundant across its habitat, it is now, as the saying goes, "dead as a dodo"