Reality is complex, with many variables. Hence any blanket assumption is likely in many cases to be unhelpful. One cannot say “violence is never the answer” because sometimes it is the only remaining option available. For example, someone breaks into your home and is clearly intent on mutilating your young children. You could call the police but by the time they arrive your children will be dead, and besides, calling the police is merely outsourcing violence as they will need to take action to restrain or injure or kill the intruder. You could stand by and watch your children being mutilated and killed because you genuinely believe non-violence is always and forever and in all circumstances the right thing, but then you are enabling the violence against your children. In other words, there are many situations where empty posturing is a dead-end that leads in all cases to an outcome of violence.
The question for civilized people therefore is “under what conditions does the application of violence result in less overall harm than abstaining from violence would cause?”
Remember the trolley car thought experiment: it shows clearly that there are no simplistic one-size-fits-all solutions in the real world.