Question

One reason many environmental anthropologists are skeptical of overpopulation as a sole explanation for environmental degradation is that it doesn't recognize that different societies and people within each society consume differing amounts of resources.

Answer 1

That statement is true.
Overpopulation could be made a sole reason for environmental degradation if the overpopulation is not followed by necessary technological development.
Due to the knowledge and  technology that we has today, these critics argue that humans can still make some sort of leeway to still preserve the environment.