Given that God is perfectly lovable, being good or goodness on the 3rd level, it must be the case that both humans in the state of pure nature and angels love God as their Creator.
Yet demons hate humans; they are implacable enemies of the human race. Humans defend themselves, and it is promised that if we win, we will imprison the demons in hell and thereby end their baneful influence forever. How can we both love God yet hate each other?
Well, it is contrary to natural law for one man to hate another. The reason is that there is a natural basis for social cooperation between humans that finds its perfection in capitalism. In a small society, it is directly contrary to reason or simply imprudent for Crusoe to kill or enslave or tax Friday. Crusoe benefits himself the most when he treats Friday justly. For his own sake, Crusoe should "adjust his conduct to the requirements of social cooperation and look upon his fellow men's success as an indispensable condition of his own." (HA, 833) In a large society things are murkier, but still crime generally does not pay. Even purely internally, crime messes up the sinner's soul. The natural morality enjoins on us the maintenance of bourgeois non-interference and peaceful cooperation, because of the dynamic and progressive complementarity of all humans under laissez-faire.
But there is no natural foundation for association between humans and angels. A human can neither harm nor benefit an angel, and though angels have the power to affect humans, such as by revealing something to them or on the contrary deceiving them, in their natural state angels would not care about humans at all and would not bother to give us the time of day. We pass like ships in the night. We coexist without cooperating.
But God would not allow things to stay this way. Angels were give the grace of charity for humans. This grace was wounding. As part of accepting the grace, the angels would be placed in a state of servitude to men. It is certainly unnatural for such great and proud creatures to serve us. It's no wonder that some angels accepted the grace and by that fact earned glory for themselves, yet some rejected this grace and became demons. Again, God would not allow them to reject charity and stay in their natural state. The rebel angels therefore decided very logically to destroy mankind so that there would be nothing below them for them to love. God's will would thereby be neatly undone.
But destruction is a black sacrament of hatred. And given what we've established, that there is no "natural sentiment" between humans and angels, for an angel to hate humans is not unnatural, is not below nature, and therefore does not corrupt the angelic nature the way Crusoe would himself be corrupted if he hated Friday.
Again, the fall of the angels had nothing to do with God directly but was a conflict between creatures. Lucifer and his host were too proud to lower themselves to serve a race so wicked as humans. It's up to us to prove them wrong and not just restore our natural dignity but still further to respond to God's grace.