Especially for Monbiot, the usual argument is that the problem is not all humans, but only the rich humans. As a biologist I can tell you this argument is invalid, because rich and poor humans are identical biologically, therefore they have the same natural propensity for overconsumption, destruction and waste, given the chance. Aside from that, “poor” humans are equally wasteful to rich humans, when you consider their huge number compared to the rich. The contribution of poor people to the climate crisis and ecological collapse on this planet is immense, despite the fact that on an individual basis it is negligible compared to rich people. What matters is total impact on the planet, not per capita.