They all are, if they’re any good. A fantasy world has to work according to its own internal logic, not a logic ported across wholesale from a real-world allegorical equivalent. Blood isn’t identical to oil; a commodity dug out of the ground is self-evidently different from one extracted from the bodies of slaves.
Nor did I start writing this story thinking, “Let’s make it about climate change.” But as I started developing the magic system of my evil exploitative empire, and realized I was writing an industrialized economy that relies on a commodity that kills people, and kills poor people more than rich people… the metaphor pretty much wrote itself, and I’m happy to run with it as far as it goes.
The element of the oil economy that I’m most interested in is the profound difficulty of changing it to something that doesn’t do the same damage; and that has to apply to the Karagond blood economy, too. If it could be solved as simply as Hegemony-wide blood drives, the only reason for the current system to persist would be pure demonic malice, which would make for a much less interesting rebellion. (It may be worth repeating again what I’ve said a couple times upthread: the theory that it’s pain/torture/terror of the victim which gives aetherial blood its power is wrong. That would take the metaphor in a direction which I think is less true to the real world challenges of e.g. the slave economy or the oil economy.)
As is generally the case in dystopian fantasy, the metaphor has an element of hyperbole; and I agree that it applies broadly to other commodities/economic processes too. That said, I don’t think there’s a non-fossil fuel commodity that plays quite the same fundamental role in so many areas of everyday life – agriculture, manufacturing, trade and transport, communications.
Well, for what it’s worth, I’ll be naming the masses; as in our own world, the benefits of industrialization will become clearer when you get out of the periphery. You’ll meet the people who will be hurt and killed by any attempt to delink the Karagond economy from blood magic. Incidentally, Princess Mononoke is one of my favorite stories about the tragedy of industrialization because it emphasizes the benefits – in particular, the lepers and prostitutes who can have power in the new world that they never could in the old.
Anyway, I can appreciate that it’s a well worn metaphor, but it’s one I think still has a lot of power and truth to it, so I don’t mind the eye-rolls from people who’ve read it a hundred times already. 
It’s true that the choice between continuing to Harrow people and allowing thousands to starve or die in war is unlikely to be entirely escapable. In the current game, that choice between killing and allowing to die is already there, on a smaller scale. (Mara is of course the one who most cheerfully chooses “allowing to die” by not stopping the initial Harrowing.)
For those who see a clear moral distinction between what you do and what you allow to happen, there’ll be no question of forced genocide. For those who think it’s muddier, the choices will be harder. But as I said to @Laguz in the PM they quoted, I think that choice is one which we face all the time (albeit in a less stark form) in various systems that underpin modern prosperity – so I intend to include it in the game.
And on that cheery note, here’s to 2017, the year when this game finally hits the app stores…