In the context that I used it, sin is a synonym for error. In your worldview, presuming to know God is an error, and those who make such claims require correction. Although you reject the substance, forms and vocabulary of religion you are dogmatic, judgemental and evangelical. A mighty church of one preaching a gospel of know-nothingism to the unwashed masses of religious FReepers in the hope of making a convert, or failing that to make someone question their faith.
Good luck with that. Or not.