Today we look around and see two polar opposites.
One side is completely convinced of one set of rights and wrongs, and are set on forcing those views on everyone.
The other side is completely set on the exact opposite set of rights and wrongs and will defend those to their last breath.
Both are fully assured that they have the moral high ground and it cannot be refuted.
How can this be? Both sides say "I don't understand how they can see it differently"

*2 Thessalonians 2:11-12 (KJV)
11 And for this cause God shall send them strong delusion, that they should believe a lie: 12 That they all might be damned who believed not the truth, but had pleasure in unrighteousness.

*Romans 1:28 (KJV)
28 And even as they did not like to retain God in their knowledge, God gave them over to a reprobate mind, to do those things which are not convenient;

Christians look back at Jesus' life and can't understand how the Jewish people completely missed their Savior, but there was a reason then too

*John 12:40 (KJV)
40 He hath blinded their eyes, and hardened their heart; that they should not see with their eyes, nor understand with their heart, and be converted, and I should heal them.

*Romans 11:8-10 (KJV)
8 (According as it is written, God hath given them the spirit of slumber, eyes that they should not see, and ears that they should not hear unto this day.
9 And David saith, Let their table be made a snare, and a trap, and a stumblingblock, and a recompence unto them:
10 Let their eyes be darkened, that they may not see, and bow down their back alway.

So you see, it makes perfect sense through the lens of God's Word.

*2 Corinthians 4:4 (KJV)
4 In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them.