Violence for self-defense is necessary
People have a right to use force or violence to defend their own lives or someone else who might be in danger. Violence in potentially dangerous situations is necessary to neutralize threats and save one's life from harm. Many laws support and protect such type of violence.Ethics Violence
It is no secret that women often take self-defense training lessons to resist sexual threats and assaults. Self-defense lessons help potential victims of abuse and harassment learn skills to fend off attackers. Even teenagers and young children are often taught how to defend themselves, physically and verbally, to avoid potentially dangerous situations.  Physical violence in the form of self-defense in most cases is the last resort and is employed by people in situations that could be of extreme danger to them. Violence in such cases is necessary because it saves one's life from harm. In some countries, by law, people have the right to defend themselves by using a sufficient level of counteracting force or violence in order to prevent a violent threat. Violence in self-defense and defense of others are justified acts. 
In some cases, unjust violence is claimed as self-defense by people. Hate crimes against minorities and marginalized people are often justified under the umbrella of self-defense. This why self-defense violence laws shouldn't exist, or it should be made sure that not all acts of violence are acts of self-defense. There are sometimes power dynamics involved between the abuser and the victim. The abuser can shift the blame on the victim's act of self-defense by playing innocent. People take advantage of self-defense laws by harming people and then blaming them for it, which is why violence isn't right even in the act of self-defense.