It still hurts relationships. This doesn't make sense. Lies decrease the love we have for one another. They diminish hope. They extinguish trust and belief in one another.
Lies are morally wrong.
Forgiveness makes us feel good, and like anything, it can be taken to excess. For example, if a person has no remorse, don't forgive him just so you can feel good or look good. It mightily confuses the liar. Likewise, don't forgive someone who has done nothing wrong. It confuses others.