God created us and nature as being imperfect. It is our imperfections that are the source of all that is evil in the World. Everything in life is about choosing to be good and in tune with God's perfection in spite of all our imperfections. This is why we have religion. Religion exists to help us get over the hump of our evil nature.
I could not have stated that better.
I, on the other hand, could state that better. Since god is the source of our imperfections, god purposely created us to do evil. So god is the creator of and responsible for evil because evil would have to exist before humanity. It first existed whithin god. That would make our imperfections not the origin of evil as you suggest. Our imperfections is just a result of another evil act.
And before you even bring up free will and choice, as I already explained it in a different thread, it's only an illusion and doesn't exist in accordance with the existence of god. I'll do a quick explanation here.
The way many theists tries to solve the problem of evil is to take god out of the equation, in other words, make god nonexistent. But there's problems in doing that. First, obviously, that would make the existence of god to be false or at very least, not the creator of all existence, making god meaningless.
Second, god exist and is the source of evil, him being the uncaused cause or creator. To go further, in which the notion of free will(or lack of) comes into play. Humans cannot have true free will because their lives are predetermined by god. Since god has foreknowledge of future events, he knows for certain, every single "choice" that each individual is going to make. This next part is where those theists drops god from the equation. Having that foreknowledge he created the first humans, designed with specific programmng in order to make he exact "choices" to properly end up where we are today. Those theists now all of a sudden are not recognising god as the creator anymore.
In conclusion, it's comes down to either god is not the source of evil making him nonexistent or not the creator of all existence, makes him meaningless. Or god exist and is evil being the source of evil.
The act of creating something to do evil is in itself evil.