I think it is just that. God knows what we are, but he also know that with him we overcome all of that. I don't think this is used to label people but rather to realize that none of us can look at someone else and say she's a fornicator, he's a liar, she's a theif... but to realize that, "such were some of (us)." Had it not been for the blood, we would be a part of "all liars" having our part in the lake... I think acknowledging that we, without God, are at least one, and probably many of the things mentioned here and many more, magnifies God's grace and the power of the blood that makes us free from the guilt and stain of sin. It also makes it possible for others who are still under that label of "sinner" which covers it all. We know and can share with them that it was no doing of our own that made us free, but it was the blood of Jesus, which is available to them as well.
As far as stepping into the role of God... I don't know if he would condemn someone for trying to adhere to the commandments even if it meant death, if that's all they knew to do. They would be doing it out of love for God and a desire to please him. I would hope that God would honor that heart and make another way for them.
Of course, the question comes to mind, "Is it even stealing if the store is abandoned?" and, "Wouldn't all of those goods eventually be wasted anyway?" It doesn't seem likely that after a storm, the merchants will come back, rebuild their store, and sell the same food items and stuff that was in the damaged store... maybe, though, idk. If nothing else, one could come back and pay them after the storm, if it was just in their heart to do right by the store.