I think it's fair to assume that violence wasn't the intent to begin with. Many times high tensions were the issue. This was a life or death situation for the strikers, who weren't being paid well enough to feed their families to begin with, who then weren't being paid at all during strikes. The factory owners were facing business-ruining situations as well — labor shortages (obviously), decreased profits, expenditures on private security, eventually being forced to pay higher wages or retrain a whole new staff. The involvement of third party actors is an important aspect to the violence as well — whether they were local militias, the National Guard, or private entities like the Pinkertons... you added (likely nervous) hired guns to an already volatile situation.

My response is based heavily on an exceptional book you'd probably enjoy reading: STRIKE! by author Jeremy Brecher.

Brecher begins his book with the story of the 1877 Great Upheaval, which began with the railroad strike of Martinsburg, West Virginia — igniting what is considered the first great American mass strike. Following pay cuts, lack of overtime pay, and increased workload, the railroad workers striked, heavily supported by the surrounding community, and even allied workers from mines, the steel industry, boatmen, etc. So much so that the strike quickly overwhelmed local militias sent to curb the issue. The B&O Railroad then persuaded the Maryland governor to get involved, who sent a Baltimore-based unit of the National Guard toward Martinsburg. They didn't get far. Here's one of my favorite quotes from the book: Said a strike leader, "The working people everywhere are with us... They know what it is to bring up a family on ninety cents a day... to run in debt at the stores until you cannot get trusted any longer, to see the wife breaking down... and the children growing up sharp and fierce like wolves ... because they don't get enough to eat." (p.17) As the Baltimore regiment marched out, the crowd stoned them "so severely that the troops panicked and opened fire." One by one the troops dropped out and went home.

This story is important to my answer because it perfectly illustrates what was at stake for the strikers, and how the unified fury of a company town could easily cause third-party actors to panic and react with violence (in turn, leading to more violence).

Several days later, in Pittsburgh, an officer of the local militia explained why troops were so unreliable at ending strikes: "Meeting an enemy on the field of battle, you go there to kill... But here you had men with fathers and brothers and relatives mingled in the crowd of rioters. The sympathy of the people... was with the strikers proper." (p.20)

So they brought in troops from father away — from Pittsburgh's commercial rival, Philadelphia. "The troops began clearing the tracks with fixed bayonets and the crowd replied with a furious barrage of stones, bricks, coal, and possibly revolver fire. Without orders, the Philadelphia militia began firing as fast as it could, killing 20 people in 5 minutes as the crowd scattered." (p.22)

In this instance, violence again erupted from a high-tension situation: rightfully angry townspeople pitted against imported troops with their own reasons to hate Pittsburgh.

And this pattern repeated itself across the country. Company owners would try to take back control from strikers by importing strikebreakers and militias; strikers would then be angered by these tactics and lash out.

In San Francisco, still in 1877, Chinese workers were already poorly regarded by the average American of the time... their use as strikebreakers fueled racism that already existed, and led to violent attacks and property damage. Similar situations across the country would make use of black Americans, all to agitate racism strikers already felt.

An aside about the troops brought in to dispell strikes —1877 was a particularly brutal year to be in the U.S. Armed Forces. You'd likely been forced into military service by unemployment, and you were either dying in battle against indigenous people on the frontier, or having bricks thrown at you by angry strikers in cities across the country. As Brecher notes, "Most of the enlisted men had [also] not been paid for months, because Congress had refused to pass the Army Appropriations Bill to force the withdrawal of Reconstruction troops from the South." (p.30)

Quite the vicious cocktail, maybe it's easier to see why things became so violent, so easily.

My interest in labor history started because I study Chicago history, and those two things are very intertwined. So... two more examples of high tensions and retaliatory gestures leading to violent strikes, both occuring in Chicago.

The Haymarket Affair of 1886 is the first, and much scholarship has been written about it. But Brecher approaches it from an angle I appreciate. He points out that Chicago had been the heart of the movement for an 8-hour workday since perhaps as early as 1884. And "the other side prepared as well. More than a year before [the Haymarket Affair], newspapers had reported the formation of military bodies by businessmen, who armed their employees... and the enlargement of the National Guard." Local police, as well, prepared for the inevitability of strikes (by this point, strikes and their capacity to turn violent was well understood). (p.54)

The day before the Haymarket Affair, an angry crowd attacked strikebreakers brought in to the McCormick factory. Local police fired on the crowd in response, killing four and wounding many others. The following day, May 4th, a protest against police brutality was planned at Haymarket Square. Lecturers spoke, all was peacefully beginning to wind down for the day... then someone threw a bomb. We're still not sure who. As the writeup I link below notes, "the police panicked, and in the darkness many shot at their own men. Eventually, seven policemen died, only one directly accountable to the bomb. Four workers were also killed." http://www.illinoislaborhistory.org/the-haymarket-affair

High tensions between police and protesters at an event protesting police brutality, one day after an incident of police brutality? It's not unsurprising things went the way they did. Did anyone intend for things to turn out that way? No, certainly not. The incident had a disasterous effect on labor movements nationwide.

As the century came to a close, there was a shift, perhaps where you could argue the violence became more intentional.

George Pullman was an absolute dirtbag. Everyone he knew it. He was famously buried in a thick layer of concrete because his family was so certain people would want to try and dig him up and desecrate his body. https://www.gracelandcemetery.org/merchants-and-inventors/

Pullman ran a company-owned town on the edge of Chicago. Following the Panic of 1893, he cut wages dramatically, but didn't lower any of his employee's rents. Brecher notes, "One man [had] a pay check in his possession of two cents after paying rent." (p.85) This all in addition to Pullman actively working to reduce the number of skilled workers at his factories, changing the manufacturing process to his benefit and to his workers' dismay. https://digital.lib.niu.edu/illinois/gildedage/pullman

His workers unionized, as one could expect, and striked in the spring of 1894. Fellow railroadmen, in solidarity, began boycotting Pullman's namesake train cars, refusing to handle them. Massive disruptions to rail traffic across the country resulted, with businessmen soon calling for the federal government to intervene in the name of restoring law and order. President Grover Cleveland was more than happy to send troops to Pullman to quell the striking workers, a decision widely expected to incite violence. Eugene Debs, then working on behalf of the strikers, predicted bloodshed, as did General Nelson, commander of U.S. troops in Chicago. (p.92)

Upon the arrival of troops on July 4, 1894, strike-sympathizing crowds immediately gathered on railroad property to cause havoc. Fires broke out, and soon, so did gunfire. "...a railroad agent on the Illinois Central shot two members of a crowd. The crowd retailated by burning the yards." (p.93)

Thirteen people were killed, and fifty-three were seriously wounded. Sympathetic uprisings happened in cities across the country, and several others turned violent as well. Public opinion, swayed by ghastly news reports, turned against the strike.

And the saddest thing of all was that the workers didn't win. The strike fizzled out under unrelenting pressure from the federal government, local government, union leaders, and even the public. Most of Pullman's workers returned to work that September, forced to renounce their union. As Debs put it, and Brecher quotes, "...the corporations are in perfect alliance; they have all the things money can command, and that means a subsidized press, that they are able to control the newspapers... the clergy almost steadily united in thundering their denunciations; then the courts, then the State milita, then the Federal troops; everything and all things on the side of the corporations." (p.98)

All of this is to say: violence wasn't originally the intent of corporations or strikers, moreso just a natural reactionary result of high tensions and life-or-death stakes. The lines between striker and corporate agent were blurry, and often easily dissolved. As the years wore on, however, the corporations got smarter in predicting how strikes would play out, and employed strikebreaking tactics more likely to result in violence — playing racism to their advantage, importing highly trained military forces from long distances away, and using alliances with government officials and other powerful entities to make strikers feel powerless and backed into a corner.