I think some nuance that is being lost is people aren’t distinguishing the difference between violence as self defense, violence as protest and violence as a mechanism of justice.
Violence as self defense is often justifiable- when someone is trying to do you harm and you’re using it to protect yourself. Violence as protest, as we saw during Stonewall and some of the BLM protests, can be an effective response to oppression, as a form of disruption. Sometimes it’s an effective form of counter protest too, like the punching of Richard Spencer, for instance.
But violence becomes highly dangerous once it becomes a mechanism to mete out punishment. Whether this is through an organized state apparatus or mob rule/vigilantism, the costs to human rights are staggering. We see time and time again that the most marginalized people pay the price. People of color are disproportionately subjected to the death penalty. Black men were targeted by lynch mobs. Cops and white vigilantes extra judicially kill Black people. Authoritarian regimes like China and the USSR have frequently targeted lgbtq people and ethnic minorities.
People who argue violence is never justified ignore crucial moments in history when it played a major role in protesting for human rights, or when people must resort to it for their own survival. But advocating for retributive justice is not going to serve progressive causes ultimately. Violence is at best a temporary stop gap that should only be resorted to when necessary. It is not a permanent solution and it will never work as a form of justice because justice is about repairing the harms of a society–violence cannot repair. And violence as justice becomes a form of societal control and a mechanism of power. And that is why the most marginalized always lose when that happens.