Please provide each passage where you think God says all humanity is written in the Lambs book of Life. What you wrote above is vague. I would like to read the exact passages of scripture that make up your argument.
I have never heard anyone make your argument before so I find it hard to see your position being obvious in scripture when no one else has made the claims you are making.
Revelation 5:9-10
9 And they sung a new song, saying, Thou art worthy to take the book, and to open the seals thereof: for thou wast slain, and hast redeemed us to God by thy blood out of every kindred, and tongue, and people, and nation;
10 And hast made us unto our God kings and priests: and we shall reign on the earth.
Now the saved are singing this song, because they died in Christ. They are there under the alter: Revelation 6:9-11.
Later, Revelation 5:13
"And every creature which is in heaven, and on the earth, and under the earth, and such as are in the sea, and all that are in them, heard I saying, Blessing, and honour, and glory, and power, be unto him that sitteth upon the throne, and unto the Lamb for ever and ever."
This happened before the Lamb started unsealing the book. What book? Revelation 5:1-5.
"And I saw in the right hand of him that sat on the throne a book written within and on the backside, sealed with seven seals.
2 And I saw a strong angel proclaiming with a loud voice, Who is worthy to open the book, and to loose the seals thereof?
3 And no man in heaven, nor in earth, neither under the earth, was able to open the book, neither to look thereon.
4 And I wept much, because no man was found worthy to open and to read the book, neither to look thereon.
5 And one of the elders saith unto me, Weep not: behold, the Lion of the tribe of Judah, the Root of David, hath prevailed to open the book, and to loose the seven seals thereof.
This can only be the Lamb's book of life. It was started after the Atonement and the vail of the temple was rent. It was for all the world. John 1:29, John 3:16 This was God’s plan since before the beginning of the world. It contains the names of all humanity from Day 6 to the last human born on earth. No name was left out, because the fact as pointed out by Moses, names have to be removed. Exodus 33:31-33
31 And Moses returned unto the Lord, and said, Oh, this people have sinned a great sin, and have made them gods of gold.
32 Yet now, if thou wilt forgive their sin--; and if not, blot me, I pray thee, out of thy book which thou hast written.
33 And the Lord said unto Moses, Whosoever hath sinned against me, him will I blot out of my book.
The Lamb's book of life was sealed at this time. The book is still sealed. There have been no names added nor removed from the time of the Atonement, but not just 30 AD. The Lamb slain from before the foundation of the world. The Post glorified body of Jesus Christ was there in the beginning just as John in John 1 claimed. Everyone written in the book, both sinner, and redeemed. Only at the end of the church age when the 7th Seal is opened will God begin removing names. The first will be all those who have accepted the mark of the beast. Then at the Great White Throne judgment will be the final roll call, and all the names of those rejecting Christ will be removed. Matthew 7:23
"And then will I profess unto them, I never knew you: depart from me, ye that work iniquity."
God knew all in the Lamb's book of life, everyone 2 Peter 3:9. After being thrown into the lake of fire and removed from the Lamb's book of life, God stopped knowing their very existence, just like those sins of those redeemed.