The World Health Organisation defines violence as "the intentional use of physical force or power, threatened or actual, against oneself, another person, or against a group or community, which either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment, or deprivation."
People are often exposed to violence in the media, such as movies, video games or the news, but there is a psychological distance between the audience and the violence that is happening on screen. Also, the violence depicted in movies is dramatized to such an extent that it becomes a parody of real violence. This is especially true for the martial arts. Many films and video games depict characters fighting or duking it out in hand to hand combat, getting up or continuing to fight after taking hits that would render a normal person unconscious. This is artistic licence, but because most people don't experience real violence, they tend to equate this dramatized violence as the real thing because they don't have personal experience to compare it with.
I have found quite often that prospective students who attend martial arts dojo are under the illusion that what is being trained is the same as the dramatized violence they see in the media, then suffer a rude shock when the reality of true violence is displayed or experienced. The result of this experience is often leaving and never coming back after the first class.
In my classes I go to great lengths to ease new members into training, but it is difficult to alter a curriculum to such an extent as to shield participants completely from the reality of what they are training.
Martial arts are violent. They are supposed to be. They stem from a time when the world was more chaotic and less civilised than it is today. But, martial arts didn't promote an uncontrolled violence, it sought to focus violence into a surgical tool to be used at the right time, in the right place, in the right way.
To prospective students of the martial arts I encourage you not to give up after the first class, even if you encounter activities or philosophies outside your comfort zone. Violence is a natural part of society and should be understood and controlled, rather then suppressed. A society that understands violence is resistant to it, a society that represses violence is prone to succumb to it when systems break down.
Violence, given or received, helps people grow and tempers the psyche. It is safer to rely on a notched blade that has withstood a battle, than to rely on a new blade that has never been drawn.
