God's people are lost because of insufficient love for Truth, i.e. insufficient love for Him.
That is also de fide, because it explicitly stated in the Bible.
"And in all seduction of iniquity [sin] to them that perish; because they receive not the love of the truth, that they might be saved. Therefore God shall send them the operation of error, to believe lying:" 2 Thess. 2:10-11/DRV
The lie of the earth being a globe is a powerful delusion, so powerful that it is nearly universally believed. Those who have broken free from this terrible delusion have responded to the grace God has given them to believe their eyes, their senses, and His Word.