Forgiveness hinges on proportional response and context; a headbutt is a sharp breach of fair play. It scars that final's memory.
Final ground demands honor; a headbutt breaches the rules of engagement and taints the game’s memory. Forgiving it invites future breaches and weakens discipline.
Forgiving it cheapens virtue and tilts incentives toward aggression, eroding the sport's trust and its market for fair play.