It is simple.
God is perfect and Holy.
As Gary said, He cannot allow sin into heaven, therefore we are ALL condemned, not by Him, but by ourselves for OUR own sins.
But God loves us so much that He paid the ultimate price so that we can be with Him.
The blood of Jesus cleanses us from ALL our unrighteousness. So that in God's eyes, it is as if we have NEVER sinned.
You say over and over that God murdered His son. Well, that is not true.
If you want to look at God and Jesus as two separate persons, than you need to know that Jesus willingly laid down His life for us. That was His choice, and He could have just said, "No I won't do it."
You also accuse God of being unjust for the condemnation of those that do not accept His gift. Let me ask you.
Say that I found out that I needed a heart transplant or I would die, and your very own son took pity on me, to the point that he was willing to lay down his life and give me his heart. He goes to the hospital and has the doctors remove his heart and then he dies. The doctors come to me and tell me that I can now live because they have found me a heart. And then I say, "This person and his father is a fool! I don't need it and you can't make me receive it. Get away from me and speak of this fool no more."
Your son has layed down his life for me, and all I do is ridicule him and you.
So, are you going to take me to the bar and buy me a drink and be my buddy, or would I experience "The Wrath of Dan?"