Violence is omnipresent.
To deny this, is to deny our humanity, our ability to change, to evolve.

The question is : why is violence systematically and dogmatically considered as an evil ?

In our society, progress is an absolute value while destruction and regression are in contrast with the actual vision of the world. However, the idea that violence can be considered as a source of progress is deeply registered in each of us. There are several major steps of our evolution which were triggered by violence : French revolution was one of the most barbarian period of modern times but brought us the human rights. American Civil War was a bloodbath but helped make a huge step towards the abolition of slavery.
Of course, for every positive example, you can give two negative ones. My point here is not to convince or prove that violence is always useful, but to bring up the questioning in ourselves and our community, engaging us to doubt. Doubt that could bring another perspective on violence.
So, violence can be “good” if it shows and provokes deep positive changes that go beyond all its destructive consequences.
We often notice violence through destructive behavior. But there are different kinds of violence that exist without any sort of destruction : a kind of calm and quiet violence, inert, which is often the worst. Indeed, the changes done through violence, the evolution, are due to the energy it generates, to the conflicts created. While on the other hand, the so called quiet violence paralyzes more than it awakens.
Although it can be found anywhere, this last kind of violence is too often neglected and ignored. We can observe it where the violence is inherent to the place itself. A gloomy empty train station for example or a dirty silent empty street… We tend to feel oppressed by such environments without being able to explain why, which as a result leads us to completely interiorize it.
One of the principal causes of this omnipresent violence, which is often too minimized, is fear. Fear is of course necessary for humans in order to react to our environment, but it can also cause immobilisation. Phobias for example can be real handicaps for someone who really cannot face it. We think of claustrophobia or agoraphobia for instance, but there are various kinds of “unreasonable” fears which can be the cause of inability to act, inefficiency and total uneasiness.
This happens when fear is stronger than the threat. The fear of violence follows the same laws. It is logical to fear violence in order to avoid it, but when this fear of becoming a victim of that violence is bigger than the actual risk, we enter a world of constant suspicion, trying to defend ourselves from invisible aggression.
This tranquil and quiet violence I exposed here-above precisely creates that kind of unease. It is indeed so present in our everyday life that we tend to develop fear in order to avoid it. But since this violence is present everywhere, it leads us to close up on ourselves and to immobilize us. And finally, being scared of that kind of violence leads us to reinforce it, or at least to reinforce its effects instead of fighting them.