You can't progress, move forward, or grow without bringing with it the ability to digress or fall.
I wish I could say it in cooler words than that. Alas, my skills lay not in that area. But I think, or rather hope, that you get the idea.
Newton was way more correct than he realized when he came up with his 3rd law. Every action has an equal and opposite reaction. That isn't just a physics law. It's an integral part in the non-tangible universe as well.
It's interesting. People are always writing, reading, talking, or singing about a world with all good, and no bad, and some of them even explain how God is a terrible God for letting bad things happen in the world. While I don't have anything against the songs and books and whatever, I think most of the people who write them are missing the point.
When you climb a cliff, you leave a gaping space behind you which you could conceivably fall through. When you become a better person by working on different traits or habits, you leave behind you an old way of being.
I'm not saying it's pointless to grow. Rather the contrary. But I am saying it's possible to fall. You probably won't fall off the cliff if your equipment is right. 99% chance you'll be fine. But you can fall. If you grow as a person, you won't want to go back to your old ways, and there's nothing saying that you have to. But you have the ability to. That's the point.
Falling, digressing, messing up, making mistakes... that's all an irrevocable part of a non-stagnant universe. We either have nothing or we have both good and bad. We can't even have good without bad. We just can't have happy without sad.
Good isn't good without bad.
Everything in life is that way. Equal and opposite reaction.
Take the internet. Think of all the amazing good it can do. Research. Knowledge. Keeping in touch with people. The list goes on. But with it comes the unfortunate but inseparable ability to do bad.
Or music. Music is a POWERFUL thing. It can be incredible. But that doesn't come without the natural consequence of being able to have awful music. And by awful I don't just mean poorly written. We're talking actually bad music.
EVERYTHING is that way. It's the law of the universe.
So, it has nothing to do with God wanting bad things. It has nothing to do with Him not caring. It has nothing to do with Him being a bad God or not existing at all. (In fact, the balance between good and bad that exists is really a sign of God's existence.)
What it does have to do with is the fact that there are laws that exist. Without those laws, things just can't exist. It all becomes unstable, breaks down, and disappears. God uses those laws to make things work. He doesn't go around breaking laws because His creations wouldn't function if He did.
I'm sorry I'm so bad at explaining things. I wish I could do better. I wish I had the skills of fluid speaking and explanation, but I don't. I hope you got the idea of what I was saying.