Jesus said we are to forgive regardless. He said we are to love others regardless. Whatever the young man in South Carolina did previously did not warrant him being assaulted.
To reemphasize, if someone has offended you and you bring it to his or her attention, if the offender has asked forgiveness and attempted to make it right, your requirement is to forgive them. And how will the other person know that you have forgiven them? It is through these three simple words, “I forgive you!”