This logic has some superficial appeal, but it just doesn't hold water. Let's say a king wants to rescue an ugly slave woman by purchasing her freedom, bringing her to his castle to live, giving her a royal wardrobe to replace her rags, beautifying her with the help of the court plastic surgeon, and marrying her. Seems like a pretty good deal to me. I would go so far as to call it a gift, even though the woman would have to give up her rags and her old life, and the plastic surgery might be painful. Suppose she answers: "Thank you! I'll take the gift of freedom and marry you, as long as I can keep my rags and ugliness and stay here with my master. When he dies, I'll join you." Then she parades around in the same rags worn by the other slaves, calling herself the king's wife. Will the king accept her under those terms? Or will he demand that she give herself completely to him or stop defaming him by calling herself his wife?
Someone may reply: "But if the king bought her freedom, it's up to her what she does with it." Let's say for the sake of argument that that's true (even though the Bible says nothing of the kind). If she stays with the slave owner, she is, for all practical purposes, a slave. She has chosen to forfeit the benefits of marriage to the king. Could she suddenly wake up one night and decide to leave the slave driver? Yes, because the king has purchased her freedom. But she has to actually leave in order to enjoy that freedom.
Still, my opinions are a dime a dozen (less than that--they're free!); the real question is what the Bible has to say. Is the gift completely without condition? "For God so loved the world, that He gave His only begotten Son, that whoever believes in Him shall not perish, but have eternal life." (John 3:16) Who shall not perish, but have eternal life? Those who believe in him. Isn't that a condition? If we remove all conditions, we're left with Universalism, which most evangelicals reject. Charles Spurgeon, using the old translation "on Him," rather than "in Him," says: "The faith that saves is not believing certain truths, nor even believing that Jesus is a Savior; but it is resting on Him, depending on Him, lying with all your weight on Christ, as the foundation of your hope." That kind of faith cannot but change us.
Let's look at a few more verses: "Do you not know that when you present yourselves to someone as slaves for obedience, you are slaves of the one whom you obey, either of sin resulting in death, or of obedience, resulting in righteousness?" (Romans 6:16) "For if we go on sinning willfully after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, but a terrifying expectation of judgment and the fury of a fire which will consume the adversaries." (Hebrews 10:26-27) "God has chosen you from the beginning for salvation through sanctification by the Spirit and faith in the truth." (2 Thess. 2:13) Salvation is through sanctification, by the Spirit and faith. This is not optional. "Faith without works is dead." (James 2:26) "For all who are being led by the Spirit of God, these are sons of God." (Romans 8:14) Does God's Spirit direct our lives? If so, we are sons and daughters of God. If not, we are like the woman living in sin with her slave owner, while pretending to be married to the king.
But God's word also says: "He is mindful that we are but dust." (Psalm 103:14) The king doesn't expect his new bride, rescued from slavery, to be the perfect wife right away. She'll have relapses for some time as the slave driver tries to get her back. There will be times when she believes his lies, and the struggle will not cease until he is dead. But if she is the wife of the king, she can't ever go back to live with her old master.
Just like we can't ever make peace with our sins.