It doesn't have anything to do with the planet carrying capacity. This is only about the speed of viruses to spread, which is higher in dense and connected areas (and the quantity of meat we eat since diseases often come from meat).
In TFA, there's the argument that human invasion of more and more wildlife habitat has increased the risk for zoonosis:
> Yes. EcoHealth Alliance, an NGO, and others, looked at all reported outbreaks since 1940. They came to a fairly solid conclusion that we’re looking at an elevation of spillover events two to three times more than what we saw 40 years earlier. That continues to increase, driven by the huge increase in the human population and our expansion into wildlife areas. The single biggest predictor of spillover events is land-use change—more land going to agriculture and more specifically to livestock production.
And about meat, there are two issues. One is about impacts of livestock production, and the other is about wildlife consumption.
We are overpopulated but that's not changing any time soon so we all need to find ways reduce our ecological footprint now. Cutting way back on or eliminating animal products from your diet is one of the best and easiest ways to do this.
