I think the larger argument that I am making is that violent change brings about a reaction that often nullifies the gain. Obviously entire volumes could be written about this, but let me address the questions you raise one at a time.

1. The American Revolution certainly embraced violence, although it was usually coded as self defense. In our popular mythology a bunch of heavily armed farmers resisted high taxes and imperial control. Other land speculators took advantage of the crisis to seize the estates of loyalists, expand slavery, and confiscate Native American lands. Now we are a global superpower that is happy to bomb and occupy real and perceived enemies, while resisting the taxes needed to fund a competent state? Are we feeling free and secure today?
2. The French Revolution became a parody of itself as Jacobins sought to literally decapitate their political enemies while remaking society. They were inevitably replaced be conservatives who paved the way for Empire and then the restoration of the monarchy. While they inspired future generations to fight for change the violence it unleashed may far outweigh the benefits.
3. The United States Civil War succeeded in reuniting the country and abolishing slavery. But the Confederacy has lived on in the imaginations of Americans both North and South. We are still fighting about racial equality, the disproportionate power of southern elites, and how to remember a war fought for the “States Right to enslave Africans.” The peace in the 1890s specifically denied the role of slavery and Black soldiers in the conflict. (See David Blight’s Race and Reunion for the full story.)
4. I am a member of a labor union. At the same time violent measures adopted by unions in the late 19th century and beyond often led to brutal suppression and the identification of unions with communism and anarchism. Organized labor has been gradually losing power and influence since the 1950s. A favorite tactic of management was to actually provoke violence so that union leaders could be blamed and unions discredited.

Many other examples could be applied. In the PBS documentary The Great War and the Making of the Twentieth Century, the historian Jay Winter claims that the problem with revenge is that it leads to more revenge.

The great mid-century American Theologian Reinhold Niebuhr wrote, “We must be saved by hope, because nothing that is worth doing can be accomplished in a single life time. The greatest positive change comes through people who inspire the next generation to fight for a more inclusive and just world. When they adopt violent means to peaceful ends they almost always fail. As Dr. King wrote, “The ends are inherent in the means.”