If you have been warned not to do something then you are going to be punished. If you have not been warned and you do something stupid then the person who was supposed to warn you and didn't warn you will be held accountable. That is basically the moral of this chapter. God tells the people of Israel that he has assigned them as sentinels to tell the people that they have to turn from their wicked ways, turn away from the false idols and eating non kosher food or else God will destroy them. If the people who were evil turn away then God will save them. If the people do not turn away then God will destroy them because they were warned and did not heed the warning.
Really, really interesting potential parallel to where we are finding ourselves today as we have been warned that if we do not take this virus seriously then we are going to be reaping the negative effects of it. I find it shocking that some people are wondering why things are so negative when everyone is following the CDC guidelines when in fact people simply are not following them. This chapter lays out the basic moral of the story for us as we find ourselves in the midst of this pandemic. We are never guaranteed our safety, but if we know that doing certain things saves lives and we do them, great. But when we do not do them then we should not wonder why things are so bad. Those both who do what they are supposed to do and those who are not doing what they are supposed to do will both suffer. We live in a community where each person will thrive or suffer based upon what our neighbor is doing.