Ok so I personally disagree with using violence to convince someone of a political position. However I certainly recognise that in certain cases it can be an effective expedient, and in certain cases the only option if one doesn't simply wish to “thrown themselves into the sea from cliffs” which Gandhi proposed the Jews do in facing the Nazis. I don't agree with Gandhi that we should have lain down our arms and surrendered to the Nazis, and I dont think many others would either.

“What we are seeing here is people using violence and intimidation towards civilians into adhering to a political stance.”

So there is clearly some space for violence in politics. How and where you draw the line between justified violent resistance to the spread of a repugnant political ideology and when it becomes “unjustified immoral terrorism” is anyones guess.

Take “punching Nazis”. I was pretty against the whole idea when I first heard of it. Seemed immature and not the right way to be dealing with a fellow citizen. I felt that if you couldn't convince someone verbally then perhaps your position wasn't as strong as you thought. I thought all it would to would make people wanting to do good seem like thugs and wouldn't do anything to reduce white supremacists.

However on the other hand white supremacy is no joke and we have historical examples of what happens when such an ideology is allowed to gain traction. However even ignoring such hypothetical futures, they do not have peaceful intent for many of my fellow citizens and actively advocate or perpetrate violence against them right now, and I believe that needs to stop regardless of my or others capacity to convince them otherwise.

The thing that really changed my position was when Richard Spencer, a leading white supremacist who “supports the creation of a society run by white people in the USA and routinely attacks diversity as an assault on the white race.” said the following in a video:

“I really hate to say this, and I definitely hesitate to say this,” said the poster boy of the so-called alt-right. “Antifa is winning to the extent that they’re willing to go further than anyone else, in the sense that they will do things in terms of just violence, intimidating, and general nastiness.” He stated that the willingness of far-left activists to use any means necessary in attempts to shut down his speeches has left the far right “up the creek without a paddle.”

https://theintercept.com/2018/03/17/richard-spencer-college-tour-antifa-alt-right/

So yeah… punching Nazis works. Terrorism? Maybe? Effective too though.

So what can supposedly justify such actions to people who claim to support notions like “human development flourishes when individuals engage in cooperative, mutually respectful relations that can thrive only when excessive differences in status, power, and wealth are eliminated". (Barry Clark)

I think the violence and deaths that the BLM people claim to be caused by police brutality and systemic racism clearly fall into an area which could be seen to justify violence be used to stop it.

However lets consider some more generalised leftist aims. You said elsewhere “I'm not sure killing right-wingers is justified by better education or healthcare.” How about economic inequality? First lets take it down a notch, as while I know there are some leftists who would love a violent soviet style revolution I personally think it's a fucking terrible idea. So no killing people.

If I told you that we were going to set up things economically so that aside from all the other benefits of being rich rather than poor, we were going to put to death all those who fall below the poverty line five or years before they reach the average national life expectancy? In this scenario you may not be personally under the poverty line (thought it's not guaranteed), but you likely know someone who is.

Would such a proposal justify a violent resistance to it's advocates, or even those who passively support those advocates? Because this is a real outcome from the current US economic system.

"One of the most disquieting facts about life in the United States today is that the richest American men live 15 years longer than the poorest men, while for women it’s 10 years. Put a different way, the life expectancy gap between rich and poor in the U.S. is wider than the gap between the average American and the average Yemeni or Ethiopian." https://newrepublic.com/article/153870/inequality-death-america-life-expectancy-gap

So yeah, while I dont agree with violence, I can sometimes understand why others feel these issues are life and death. When it comes to left-wing violence vs right-wing violence, if you are afraid of becoming caught up in such violence, then to stop the left all that would have to happen is for the way society functions to get a fairer for both you and your fellow citizens. What I challenge you to do is find similar justifications, or hell even any sensible reason, for some of the things that right-wing violence are about. The only reason you think one is more scary than another is that you're quite probably not a target of common right-wing animosities, because otherwise you, like many of your fellow citizens right now, rather than turning to violence would have to be considering throwing yourself into the sea from cliffs.