> May as well just say The Earth would be better off if people had never existed if you're going to go that route.
No, that most certainly doesn't follow. It's entirely usual and normal for an amount of something in a system to be fine but then an excess of the same thing to be not fine. This is a very common situation in medicine, for example.
It's also a common situation in the rest of population and community ecology. For instance, removing wolves as a predator here in Michigan has caused an explosion in the deer population. That, in turn, changed the makeup in undergrowth as they eat more now, which has all kinds of extended effects. Not to mention the propagation of diseases in a more sense population.
No, that most certainly doesn't follow. It's entirely usual and normal for an amount of something in a system to be fine but then an excess of the same thing to be not fine. This is a very common situation in medicine, for example.