For all the regret which the fate of the Kabutops has brought, it does no good to forget this world's own history, or to sanitize it so that it can be reduced to a simple tale of Man vs. Nature, casting Man as the villain. It is true that Kabutops were literally blood-drinkers: this was their primary way of feeding, as indeed it had been for the past 300 million years. It is true that on occasion, they would kill and drink the blood of human children who wandered away from civilization, but Kabutops were not the only predatory pokemon to kill humans, and wiping out the Zubat and the diseases they spread would have saved countless more human lives. And perhaps it was true that in the old days they had been humanity's rivals, for a fear of Kabutops is reflected in most human mythologies.
It is also true that the human campaign to exterminate them was an absolute travesty, one which, with modern fossil revival technology, we are only now beginning to undo. Kabuto larva murdered in their caves, Kabutops ripped from pokeballs and trainers who resist killed with them; the atrocities need little elaboration. Many environmentalists fought back, and others hid them in their homes. In time, their brutality became their own worst enemy, xenocide led to rebellion and then to war, and those who decreed it were murdered by a brigade of Kabutops trainers, and humans and pokemon alike partook of their blood in a victory feast.
But although many breeding pairs survived, it was too late. The remaining Kabutops faced a population bottleneck, and despite their larva becoming prestigious samurai helmets, they were wiped out in a couple centuries by an epidemic disease to which the inbred survivors had no resistance.