No my friend, I can't buy that logic. Sin and wrong-doing are not the same thing, and I'm sure you'd agree with that. Sin is a particular category of wrong-doing defined very specifically in the context of a particular set of religious beliefs which I have rejected as not particularly useful and very unlikely to be true. Sin in religious terms is a transgression of a divinely sanctioned law or practice, and since I do not believe in any divinity, I reject that concept of sin as meaningless. But that doesn't mean I'm unaware of wrong-doing in myself and others. Clearly, people do wrong, I'm sure we'd agree on that too, and I'm sure we'd also agree we've both seen and done wrong. My restitution, or atonement if you want to call it that, is to the people I've wronged, not any deity.