Halsin might be able to answer that question for you, because he understands "nature".
Goblins multiply at astronomical rates, and this characteristic has persisted through each version of D&D. If the anthropogenic and abstract concept of "value" can be applied to life, it is inversely proportional to the ease with which that individual life can and is likely to be replaced. The life of a vole or Deer Mouse is more readily replaced than that of the rodent eating snakes that eat them, so in "nature's" economy has less value that that of a rodent eating snake. This despite the fact that Deer Mice and voles are vastly more intelligent than snakes, are far more perceptive of pain and fear, and the widely overlooked fact that predators depend on their staple prey, while contrary to the popular fiction, most predators DON'T significantly limited population densities of their prey in natural ecosystems. Voles and Deer Mice go through boom and bust cycles even when rodent eating predators are abundant; they crash when populations exceed the carrying capacity of rheir habitat due yo food shortages, stress related outbreaks of disease, territorial aggression, etc. Because rodent dependent predators depend on rodent prey for long term ecological success, rodent populations are paradoxically nore important to rodent predators than rodent predators are to rodent population "health".
Tieflings multiply at rates comparable to Humans but faster than Elves, and their period of parental dependency is similar. Goblins have far higher reproductive potentials and evidently far shorter periods of parental dependency. Thus Goblin lives are individually far less valuable than those of Humanoids. Surfacer Elves by the same criteria have more "valuable" lives than Humans and Half-Elves. D&D is filled with logical contraditions; if the Lolth Sworn Drow are so ruthless and murderous towards each other, how do they avoid killing themselves off and dying out? Similarly Red Wizards have the same reproductive potentials as other Humans; why don't they kill themselves off, and in such a chaotic and murderous society where treachery is so paramount over leatning and skill, how do they even learn to become highly skilled spellcasters? They and Lolth Sworn Drow don't augment their populations by recruiting outsiders!
As anyone who studies wildlife (that means plants, fungi, and bacteria as well as animals!) population dynamics knows, "the balance of nature" doesn't exist. In stable or naturally successive ecosystems approximations of temporary equilibrium alternate with periods of instability and change. That's why ammonites, Calamites, and giant dinosaurs no longer exist.
