Why do some people not feel guilty for their sins?

Answer:

You are having difficulty because you start off with a false assumption. There is no passage that says the Holy Spirit directly makes people feel guilt. As you noted, not everyone feels guilt over sin. If the Spirit worked one way with some people and another with the rest, then God would no longer be impartial. But Paul says, "For there is no partiality with God" (Romans 2:11). Therefore, what leads us to a false conclusion contains a falsehood.

"Now the Spirit expressly says that in latter times some will depart from the faith, giving heed to deceiving spirits and doctrines of demons, speaking lies in hypocrisy, having their own conscience seared with a hot iron" (I Timothy 4:1-2). "Having their own conscience seared with a hot iron" draws an allegory from burning yourself repeatedly. After a while, you develop callouses and your nerves become less sensitive. The same thing happens to the sinner. Repeatedly sinning deadens the feeling of guilt that is naturally within us.

Jesus did say, "And when He has come, He will convict the world of sin, and of righteousness, and of judgment" (John 16:8). Being convicted of sin would mean feeling guilty about sin and the Spirit does this. But you assumed he does it directly. This verse alone doesn't tell us how the Spirit does the conviction, only that he will do it after he came to the apostles. However, if you continue to read, the "how" is answered.

"And when He has come, He will convict the world of sin, and of righteousness, and of judgment: of sin, because they do not believe in Me; of righteousness, because I go to My Father and you see Me no more; of judgment, because the ruler of this world is judged. I still have many things to say to you, but you cannot bear them now. However, when He, the Spirit of truth, has come, He will guide you into all truth; for He will not speak on His own authority, but whatever He hears He will speak; and He will tell you things to come. He will glorify Me, for He will take of what is Mine and declare it to you" (John 16:8-14).

"How" then is explained. The conviction of the world of sin is accomplished through the message the Spirit gave to the apostles to reveal to us and the rest of the world. This, then, is impartially applied to everyone, though many choose not to believe it.

Actually, when you read about guilt in the Bible, it is not usually talking about feelings, it is a state of being. A person can be guilty without feeling guilty. For example, "This is the way of an adulterous woman: she eats and wipes her mouth, and says, "I have done no wickedness" " (Proverbs 30:20). The woman is guilty of adultery, but she feels no guilt. Others are guilty of sin and feel that guilt. "For my iniquities have gone over my head; Like a heavy burden they are too heavy for me" (Psalms 38:4). The difference is that one doesn't care and the other wants to please God. Thus, God doesn't directly make the feeling. The feeling comes as a response from the person's own view of what he has done.