Sometimes I feel like Love is a motivator. Changelings might be devoid of loving, and in a way they conquer other kingdoms in the vain attempt to gain love of their subjects. Their species is in a constant state of decay as they try to gain love. They're the misunderstood, suffering species, which makes them perfect for villains. It's really sad, in my headcanon, and how I see it, they're the misunderstood child who doesn't know that their forceful method of loving is... inappropriate.
Though I’ve addressed the feeding of love in a couple of these posts, I’ll say this: Changelings are indeed a misunderstood, suffering species in Papi’s canon, and for some interesting reasons.