Yes, people need to know what they are doing, for if they truly know the ramifications and consequences, they would not sin. As much as we can promote awareness of consequence, and condemn lack of awareness, there is so much more to knowing what we are doing than simply “knowing it is a sin”. A person who is not mindful of consequence in the moment may sin, and this blindness is a demonstration of not knowing what they are doing.
The important word in your additions here are “should”. The important word in my question is “does” or “is”.
Have you read the writings of recent popes? There is much more focus on “eternal life” as it begins right this moment. Jesus’ ministry was about setting people free from slavery right now, at the moment He addressed them, not just after they die. So when He said “forgive them, for they know not what they do”, He was giving all of us the means by which we can forgive at a deeper level right now, and overcome our grudges and negative feelings toward people. It is true, we can relate to the worst actors alive and in history because all of us do not know what we are doing when we sin.
… remember, I am working from “is” not “should”… “Should” is a great topic, but does not enter into truly understanding people.
I think you are saying that people resist knowing that a sin is a sin. Yes, I think that does happen. When it does happen, does the person know what he is doing?
In my observations, the answer is no. The person is not aware of the ramifications of the sin.