Is there a fundamental difference between committing a sin after one was told it was wrong, and committing a sin without knowing it was wrong?
In general, the level of responsibility one bears for a sin is directly related to the understanding one has of the severity of the sin. For example, in general, one who honestly does not realize that plowing on the Sabbath is forbidden would not bear the same level of responsibility as someone who understands that it is forbidden. The greater understanding one has of the sin, the greater the responsibility.
In addition, while ignorance may be accepted as an excuse for responsibility, a person has an obligation to learn and study. And again, the more opportunities one has to learn, the greater responsibility one has to understand all the laws of the Torah. As such, a person may be responsible for a sin if that person should have known it was a sin.
However, all that is in general terms. We can never know what lies in a person’s heart. Only G-d can truly judge a person’s action. On a micro level, we can never know the level of responsibly one bears for individual sins, for there are so many factors involved, and we can certainly never judge a person for his actions.
I hope I have addressed your question to some degree. If I have not, or if even have further questions, please do not hesitate to respond.
Be well,
Rabbi Yoel Spotts