I wrote "God sees us all as rotten until we are made new through Jesus Christ".

Its not a quote from the Bible. Is it true? We can debate that. By rotten I mean physically and morally corrupt. Our flesh and blood cannot inherit the Kingdom of God. It needs to be changed. That will happen later. (Romans 8:23). Our flesh and blood is like everything in this world slowly falling apart. Our brains also start to lose function after some time.

But worse than that, "our righteousness is as filthy rags" (Isaiah 64:6 and according to the book of Romans, chapter 3

Rom 3:10 As it is written,“There is no one righteous;
no, not one.

Rom 3:11 There is no one who understands.
There is no one who seeks after God.

Rom 3:12 They have all turned aside. They have together become unprofitable. There is no one who does good,
no, not, so much as one.”[2]

Rom 3:13 “Their throat is an open tomb. With their tongues they have used deceit.”[3]

“The poison of vipers is under their lips;”[4]

Rom 3:14 “whose mouth is full of cursing and bitterness.”[5]

Rom 3:15 “Their feet are swift to shed blood.

Rom 3:16 Destruction and misery are in their ways.

Rom 3:17 The way of peace, they haven’t known.”[6]

Rom 3:18 “There is no fear of God before their eyes.”[7]

Gen 6:5 Yahweh saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually.

Even though we are rotten and fallen before Christ changes us, God still loves us. But where in the Bible does it say why God loves us? I think the answer is because it is His nature.