We are God's, we live because the breath of God was breathed into us. That's the core of who we are, we are all the breath of God breathed into human flesh. Don't call the breath of God defiled or dirty. But when we choose sinfully, then our own choices defile that breath of God in us which is beautiful and clean and perfect. It is what we choose to bring out of our selves which creates defilement.
Sin is our choice.
That's why God can and should hold us responsible for it. The devil doesn't make us do it, and we weren't born doing it. We choose to sin. We choose to defile ourselves. That's the blunt truth of it.