I beg to disagree. Guilt is not an inherent product of religion. Guilt is an inherent product of an immature religiosity. Those guilty feelings, as uncomfortable as they may be, are a cheap and easy substitute for a deeper, more mature sense of atonement. For some, it is easier than atonement.
Religious guilt is usually an end in itself.
I convict myself of a wrong doing and I punish myself with a little guilt. And that's the end of it. Having punished myself with a few twinges of conscience, I feel entitled to a little burst of self righteousness. Guilt is almost always a self serving emotion. Guilt demands no response other than punishment and often times we regard our guilty feelings themselves as punishment enough.