But the devils are still higher in being, so it follows that they should be loved.
Let me tentatively suggest only a hypothetical: that I think that there is a difference between loving something as such and loving something not as such. We don’t like devils for the latter reason (cause they are evil, but they are not evil as such), while we like them for the former reason (since as such, they are good).
But then again, is it true that the devils have less of an angelic nature (a damaged nature) than other angels?
Things are good to the extent that they exist, that means, to the extent that they are
beings. But because devils are called devils, not simply because they exist, but because of the wicked things they do, it would be incorrect to say that we should be loving devils, for that would imply that we should be loving what they do.
However, you are right in thinking that devils, insofar as they are beings, are good. And you possibly can love devils, if you can love them just for their being and not also for their actions. Actually, this is also how we should love a murderer, or any sinner. For a murderer is, first of all, a human being, a person who has unjustly taken the life of another person. Certainly, we can love the murderer insofar as he is a human being, but not on account of the evil that he is doing or has done.
Now, when a free creature makes the wrong choices, as when a man chooses to do evil, such a choice in a way corrupts its nature, not entitatively (or as a being), but morally, for its acts are no longer proportioned to the end of its nature. That is why a man, who commits a sin, in a way diminishes himself. In a sense, and because his will is capable of free choice, man can become worse than brute animals, whose actions are not free. That is why you don’t tell a monkey to stop acting like a nut, but you can tell a man to stop acting like a monkey, if he acts in a way that does not conform to his dignity as a person.
So, to answer your question, “Is it true that the devils have less of an angelic nature (a damaged nature) than other angels?” my answer is this: Devils, by reason for their fall or sin, have morally diminished themselves (or have morally damaged their nature), and so are regarded to be even less in dignity than human saints.