Something else to consider, for those that don't object to violence on moral or ethical grounds, is that violence is often counterproductive.
If used against powerful governments it usually results in violent crackdowns which wind up killing off and/or imprisoning the leaders of the anti-government movements.
When used against weak governments, the government may topple, but what arises in its place is often even worse than the toppled government, and that tends to be followed by much more bloodshed.
If used against the populace it tends to cause both vigilante violent reaction and a resentment of the populace against one's cause.
Violent action usually leads to violent reaction, and the moderates are killed off by those who are even less reluctant to use violence to achieve their aims.
Countries thus afflicted not infrequently are plunged in to the horrors of civil war, which suits the extremists of every stripe, while ordinary people who just want to live their life are devastated.
Non-violence however requires (!) a functioning democracy that listens to the citizens - one might argue that a democracy that listens to and serves the interests of all people is the only way for any progress that is achieved non-violently. For me, the rise in political violence in the US is not surprising at all given how more and more of the citizenship has been left behind and ignored by its representatives. And even the progress that happened in the US' recent history... a lot of it only happened after large scale riots (such as the Civil Rights Act 1968). Fittingly, it was MLK himself who said the famous quote "riots are the voice of the unheard".
Especially regarding revolutions against authoritarian regimes - I can't name even one major society that went through the change from an authoritarian government to a democracy without a war or revolution of some sort (even the British parliament's history has a couple of wars related to it). Usually, two or three revolutions, civil or external wars are part of any major democracy's history.
If used against powerful governments it usually results in violent crackdowns which wind up killing off and/or imprisoning the leaders of the anti-government movements.
When used against weak governments, the government may topple, but what arises in its place is often even worse than the toppled government, and that tends to be followed by much more bloodshed.
If used against the populace it tends to cause both vigilante violent reaction and a resentment of the populace against one's cause.
Violent action usually leads to violent reaction, and the moderates are killed off by those who are even less reluctant to use violence to achieve their aims.
Countries thus afflicted not infrequently are plunged in to the horrors of civil war, which suits the extremists of every stripe, while ordinary people who just want to live their life are devastated.