No matter how you cut it, the bikers were overly aggressive in their response to the alleged infraction.
Even if Lien did bump one of the bikers (likely engineered by the bikers) there is NO WAY that anyone could possibly concur that stalking the man and cutting his face was justified.
The Navy has a new way of determining if domestic violence occurred. One of the criteria is to determine if the “act” was too severe in response to the offense. Example: Wife, 5’3, 100 lbs, slaps husband in the face. Husband, 6′, 200 lbs, puts his hands to her neck and throws her down, causing unconsciousness and bruising. While the wife’s behavior was not appropriate in any fashion, the response of strangling was too much. He could have made other choices.
Thus, Lien bumping a biker should NEVER have resulted in such extreme violence. The bikers are at fault and should be held accountable.