There are many cases of violence in which the perpetrator does not engage in gambling activity. Violence can be relate to the upbringing from being a kid witnessing violence which the kid will grow up thinking violence can be justified if inflicted on someone who he thinks deserves it.
But for a grown-up man, it's more of a money problem that makes him irate with his surroundings. For a man who can't do something to earn, he will really be irate and would seek someone to blame. It's not always a gambling addiction but you will relate it to gambling addiction if the guy loses money and turns violent.
A person can be violent regardless if he's into gambling or not. It can be because of his childhood trauma and past but that shouldn't be a reason enough to fall into gambling addiction or even hurt the people around him.
We can't always blame our past or even our environment because it is our personal choice to do gambling . We can actually manage to control our emotions if we are wise enough to do the right things efficiently. It will always be our personal choice on which path we shall take. We can gamble without violence or without hurting anyone.