Taken from Paul Zimmerman's notes in the early part of 2003, combining several entries into one for completeness. This entry provides a rebuttal to the belief that God needed to create evil in this world, as an excuse for his not making a world without evil in it. Here is a link to one of the original posts on Beliefnet from which this was derived.
I was recently asked the converse question to the (supposedly unanswered) question associated with the problem of theodicy. While that question asks "If God is good and as powerful as he claims to be, why is there evil and suffering in the world?", the converse question is "If God is bad (as Maltheism asserts him to be), why is there good in the world?"
Allow me to present an answer.
Theophiles would tell you that "good needs evil in order to exist." They use this as an apologetic excuse for why God created evil—he "had to." They also claim that if he did not create evil, there would be no free will.
Both these claims are patently false. Good could certainly exist without evil, but would not "stand out" as something distinct from "anti-good" (ie, evil) if there were no evil. It would not be labeled as something "special" distinguished from some "opposite," but it could and would still exist.
The notion that free will requires the existence of evil is also nonsense. Those offering it assert that, without evil, we would have no free will, and thus be "robots" or "slaves." This notion makes it sound like there are only two choices, to do "the good thing" and to do "the evil thing." In reality, there is a near infinity of possible choices, even if you remove all the "evil" choices (or, more accurately, if the world had been created so that nothing resulted in harm and evil).
Further, remember that God claims to offer his followers a place of infinite bounty where there is no evil but where we are NOT robots or slaves! Is God lying about the existence of this place? (It also begs the question: why would an omnipotent benevolent God put his creations in the place with evil and suffering in it rather than in the place without those things that he also created?)
Now, having said that good does not require evil in order to exist, let me demonstrate the converse—that evil DOES require good to exist.
While good does not depend on the existence of a contrast between it and "non-good" to make it exist, evil depends on this very contrast. It needs good in order to thrive and survive for any substantial amount of time. In fact, evil could not exist in a world without good! Can you imagine a world that is totally evil? It would disintegrate itself in an infinitesimal amount of time!
Imagine a world, for instance (as horrible as this might sound), where all newborns of all species are stillborn. (Note that as horrible as this sounds, it is far from being "as evil" as the world could get.) First, it would only last for one generation (or non-generation), if that long. How long could such a universe sustain itself? The stillborn babies could not reproduce and give birth to a further generation of stillborn babies, could it? The evil would be terminated by its own excesses.
Second, the presence of a mechanism for birthing new beings implies the possibility of birth and regeneration. The evil exists in the failure of a mechanism that should bring about good—as in new life. If nothing could ever be born, because the world was not set up to create and generate new life, the evil of a baby coming into the world stillborn wouldn't even be possible. If dead entities simply "gave birth" to other dead entities (eg, rocks coming out of other rocks), where there was no reasonable expectation of life emerging, would this be "evil?" Of course not. It is only within a world in which is life is possible but denied and thwarted that such a thing can be considered evil.
Evil IS evil because it lives off of good, in a parasitic fashion. It tries to take what has been produced by the good from the good for its own ends, without compensating the good or benefiting it. That is, by definition, what makes it evil. That is what evil is.
Thus, the question "If God is bad, why is there good in the world?" is easily answered: because evil requires the existence of good in order to sustain itself. And when God seeks to exploit us and feed off of our whorship forcibly solely for his own ends while claiming he is doing it "for our good," this is an example of evil.