That's because God never predestined anyone other than His plan of salvation through Christ Jesus before the foundation of the world. God is no respecter of person and all have sinned and fallen short of His glory. Only those whose names were written in the book of life before the foundation of the world remain in that book as they are overcomers through Christ Jesus being God's plan of salvation for them as they believed on the name of Jesus and repented of their sins.Yet, those verses do not say God will blot the names of his predetermined elect out of the Lamb's Book of Life.
Remember, Revelation scripture tells us there are many books of God at his judgement seat.
But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death. These are those who God blotted out of the book of life, Rev 21:8.
Rev 20:11 And I saw a great white throne, and him that sat on it, from whose face the earth and the heaven fled away; and there was found no place for them.
Rev 20:12 And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works.
Rev 20:13 And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works.
Rev 20:14 And death and hell were cast into the lake of fire. This is the second death.
Rev 20:15 And whosoever was not found written in the book of life was cast into the lake of fire.
Rev 21:7 He that overcometh shall inherit all things; and I will be his God, and he shall be my son.
Rev 21:8 But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death.