I think his point was that all of Alma's kills could be carried back to the MV by mistworkers to contribute to the food stores. I'm not sure this is actually an argument against the consequences of over hunting though. I'll address the overhunting argument though. Alma will likely not be hunting the basic game that the hunters would rely on to feed the village. Instead she would be hunting the predators present in her master's lands. As Richter has now unlocked all 4 of his powers, the power and quantity of these predators has increased. If anything is threatening the availability of natural game, it is the increase in these predators. Alma thinning their numbers would almost certainly cause a rise in the natural population of the typical hunting game, rather than decreasing it.