Jonas – excellent WOJ grab; you saved me the trouble.
Shift8 – I like your hierarchy of morality between supernatural races. I often use Demosthenes’ Hierarchy of Foreignness when considering other species, but Utlänning, Främling, Raman, Varelse, and Djur doesn’t exactly fit 1:1 in the Dresdenverse, in which creatures can be sentient and sapient, but also lack the freedom of choice. Besides, Card’s entire theory was that if you think that the alien just wants to eat your face, maybe you’re just not communicating well enough and haven't tried hard enough for peace. In The Dresden Files, sometimes the monster just wants to eat your face.
I’d agree with Jonas’ WOJ posting – it seems pretty clear that the Black Court doesn’t have free choice anymore; at least, not enough in order to choose not to live the lifestyle that they do. The Reds, I feel, are debatable. Susan certainly chose to still sacrifice her life after taking the life of another. It’s arguable that she was in the process of changing while the decision was made, but I would disagree with this. The fact that she worked as the catalyst for the bloodline curse and offered no resistance to Dresden seems like sufficient proof that she was Red Court and still had the ability to make a free choice. Furthermore, I think also that Ortega’s somewhat reasonable negotiation with Dresden before the duel and Bianca’s protective attitude towards her girls as demonstrated in Storm Front also act as evidence that the Reds had the capacity to try to be something else… They certainly seem to have more humanity than the Black Court, in any case.
When it boils down to “evilness”, your definition really depends on how you define “evil”. Is evil a matter of perspective, or is there an actual measure? After all, what might be “evil” for some could be just survival for others. A White Court vampire who doesn’t kill anyone, but steals about a year of life from everyone they encounter in order to survive and mentally influences other people into betraying their spouse, breaking apart families, might be considered a great evil… or just a lost person, like Thomas in Dead Beat, who’s just trying to figure out how to survive. There’s a WOJ somewhere (which I also don’t have access to) in which Jim states that in the Dresden Files, the good guys are the ones who are trying to give people choice and preserve that choice, and the evil ones are those attempting to take it away.
Shift8, your question was to whether the "moral monster" really existed. In the Dresdenverse, I think that it all really boils down to whether the individual has choice or not. If the individual does not have choice, then the next question would be: does this creature serve some sort of function?
If the creature has free choice, then it could not fall into the "moral monster" category; it has the capacity to choose good. It might be a really, really hard choice, but they can. A warlock, especially one who hasn't lost their sanity yet, is an example of this. The Council hunts them down and kills them because of the great evil they could do, but they are not inherently evil and irredeemable.
If the creature does not have free choice, then it must still be considered whether or not it serves a function. Consider this: right now, in our world, scientists are debating whether it is a good or bad idea to wipe the mosquito population off of the world - in essence, to make mosquitoes extinct. They are, in a sense, Djur - a monster which cannot be reasoned with, cannot change, and will continue to prey on mankind. However, they very well may have a role in our ecosystem which is critical, and their sudden absence could drastically throw off or destroy other species - be it from lack of a once-abundant food supply, or from a sudden lost pollinator (and yes, there are insect pollinators other than honeybees) or from even something so wild as a hidden symbiote that we might not even be aware of; a beneficial parasite that is passed. For us to assume that wiping out the mosquito population simply because from our perspective it is nothing but trouble is arrogance, as we don't know all that it does.
Mab and the Winter Court are a perfect example of this. Prior to Cold Days, I would have agreed with your statement - the Winter Fae are nothing but bloodthirsty monsters, incapable of free will, harmful to humanity; kill and exterminate on sight. However, we've since learned that they play an EXTREMELY vital role in the defense of reality; they're tough and monstrous because their job requires it. I would find it extremely hard to believe that the Winter Fae is the only baddie type that Jim Butcher ever created that has more than one side to it and isn't a whole-black hat. In fact, I would put money on the assumption that no enemy in the Dresden Files could be ultimately viewed as fully evil, once all is actually known about them. Therefore, I also don't believe that you could just say flatly, "Kill on sight" to any creature scott-free.
EDIT: Snark Knight's post just reminded me that there are creatures in the Dresden Files that likely don't serve some sort of purpose and are actively being exterminated - hence the Oblivion War and Ivy's true purpose. I've added one last category.
Therefore, I would suggest an alternate hierarchy, instead of "Human with desire to feed," "Beast vampire," and "Moral Monster." It would go:
Mortal (Free will, no influences)
Supernatural Entity (Free will, some influences)
Benign Immortal (No free will, not immediately dangerous to mortals)
Dangerous Immortal (No free will, dangerous if encountered)
Hostile Monster (No free will, actively trying to kill, destroy, and enthrall)
Abomination (Creature actively threatening reality as we know it)