For example, for a fully grown, normally capable adult to go on and on, making bogus generalizations about topics they cannot know, is a 'sin'. Such a self-induced habit is a waste of a human brain, and further costly in the sense that the practice can lead others astray - others being those who think the source is genuine. But those are just some of the consequences. The 'sin' lies in the knowing that one cannot know that which the bogus generalization suggests that one knows.
And that means that the practice, of making one bogus generalization after another, is basically nothing more than being willing to one big fat lie after another.