No doubt, violence was often necessary historically because fundamental human rights and other freedoms simply didn't exist, so it became nearly like a war to get them. So I agree with you on that point.

But unprovoked, modern day violence seems so inappropriate in the context of a protest, and very often moves the goal further away.

The issue is that who gets to decide if violence is an appropriate response, and where is that line drawn?

Should workers burn down their place of employment because they don't feel that the rules around bathroom breaks are fair?

Should extreme religious who are protesting any number of things be justified in killing doctors or political leaders over matters that are handled in court?

In the context of violence erupting as a means of self-defence, I can't argue against that. I don't like it, but if otherwise peaceful protesters are being shot at, then violence is a balanced response (although, it may not get them to their goal).

But I don't think I could ever agree to people burning innocent people's cars, or looting uninvolved shops, or destroying the homes and communities of regular folks.