I agree that everyone has violence in them. That is why we shouldn't make tools that allow someone to kill in the fraction of a second with zero thought available to everyone without question. Guns not only make mass murder much easier, they also make killing your wife in the heat of an argument much easier. They also make taking your own life much easier. When we know that everyone is capable of violence under the right circumstances, why do we make it so easy to do?
I guess you did not watch the video. Everybody is violent is a generalized description of our culture, a simplification for the sake of ease of description, short for having to clarify over and over again that is what most people see. The realization that there are exceptions and that such exceptions can become the norm is not part of normal awareness, and not implying here that normal is good.
Perhaps saying that everyone is human and humans are a kind of animal that survives by fight or flight would be better, but for humans it is possible to transcend being triggered. The video is of a person who in my opinion fits that bill.
That such self mastery is an actual possibility would create a completely different perspective on things.
And of course I am not against gun regulation. I am against politely action by Democrats that would cause them to lose elections To fascists. Taking from people the billion year old instinct for self defense by passing laws against a common way to do that, to kill in response to deadly threat, is like running on a political platform to ban food. You are going to lose.