"I DON'T KNOW" is a dangerous dark state to be in.
I believe that there are two reasons why a person would respond to a question with the answer "I DON'T KNOW",...
lack of knowledge
IGNORANCE: lack of knowledge
I believe the ignorant ones are the ones who don't know the difference between good and evil. Even though they do evil, because they do not have the knowledge they are considered ignorant. At one point, we were all ignorant in our sins, meaning not knowing or having the proper knowledge to make right decisions.
Paul speaking of himself admits that he was the sinner of all sinners, but he said that he did it in ignorance [1 Tim. 1:13]. What he was saying was that, he "didn't know" that what he was doing was wrong because he had not heard or come into the knowledge of truth. In the 10th Chapter of the Book of Romans, Paul states that Israel again was "ignorant of God's righteousness", as he previously was. The same zeal that he had, they still had, but he was no longer "ignorant" because of a "lack of knowledge".
Peter while preaching in Solomon's porch[Acts 3 11:21], told the men of Israel that they denied and killed Jesus in ignorance; not knowing who He(Jesus) really was. He goes on to tell tell to repent, because now they know.
Jesus Himself, said of those same men, "Father, forgive them, for they do not know what they do."
Paul writes that'God's desire is not only that all men would be saved, but also that they would come into the knowledge of the truth'[1 Timothy 2].
***Ignorance is a dangerous state to be in. No excuse to be ignorant anymore.
WICKEDNESS: confusion within
I believe the wicked ones are the ones who "know" good or what is good but chooses to do evil. These are the ones who when they are asked or confronted about what they are doing, their response at times would be "I don't know". You see they are unsure why they do what they know they ought not do. Again they know right from wrong so for this reason, I say that there is some sort of "confusion within".
In the Book of Isaiah, the prophet says, 'Let the wicked forsake his way, and the unrighteous man his thoughts; let him return to the Lord,...'[55:7]. Isaiah says that they, the wicked should 'return to the Lord', meaning that at one point in time they were once with Him and or knew Him, but strayed away to do his own thing.
Satan is called the wicked one because he himself was at one point in time with God; an angel of God, but chose to do his own thing. Knowing Godliness, but choosing to do wickedness, his own thing. Satan is the author of this "confusion".
***Wickedness is a dangerous state to be in.
[Matthew 13:49&50]"So it will be at the end of the age, The angels will come forth, separate the wicked from the among the just, and cast them into the furnace of fire. There will be wailing and gnashing of teeth."
My prayer is that these words will be a blessing to you and to those who you share it with.