Why would I want to love a god who is ultimately responsible for all the horror we see around us and through all human history?
Because He's not. He gave us freedom...what we did with it is on us. We possess no moral high ground from which to call down to God. In the last century, we killed 148 million human beings in non-religious wars. Who's that on?
How did he earn it?
"Earn" is not the right word. One only "earns" a thing when it has value exceeding that which is "owed." Otherwise, the debt is on the other side...
In any case, absent a God, no one "owes" anyone anything -- not even to be nice. It's like Dostoevsky pointed out, "If God is dead, everything is permissible." You can be just as cruel, carnivorous, violent, salacious or base as fancy may dictate...and none of it is "wrong." Like all facts in a Godless universe, it is simply a contingent fact, not a moral one. There is no morality. For morality, then, just as Nietzsche thought, is no more than a phony imposition by the weak against the strong. And the brave, amoral person will ignore it and get, as he put it, "
beyond good and evil." And if so, your defiance would be a mere gesture, a misunderstanding on your part -- that you think something is moral when it's actually amoral -- like all facts in the universe.
So "earn"? No one would owe it to anyone to earn anything.
But if God does exist, then we would "owe" Him for our existence, in the first place, and then we would "owe" others to treat them according to the best outcomes for which He created them. Likewise with the natural world...it would ultimately be His, and ours only derivatively, not a thing for us to dispose of as we pleased. We would "owe" Him to treat it rightly.
If that's all God had done, it would surely be enough. But it is not all. If God cared enough to intervene in this world on our behalf, and to rescue us from the mess we created for ourselves, then we would "owe" Him gratitude and love as a rescuer, just as we would "owe" anyone who had been unspeakably kind to us at great expense. And failing to be grateful would be a crime in proportion to the size of the favour He had done us, and which we were slighting.
So He's done plenty to "earn" what you "owe" Him. But we might ask, what have we returned to Him for His Creation and His salvation gifted to us?
What choice does the lion have?
None, of course. They are mere creatures of instinct, and do not make spiritual choices. But they are part of a world that is out of its right relationship to God, and which will never be right -- anymore than we will be -- until that relationship is fully restored.