The default oligarch orientation is to treat workers as slaves to the maximum possible extent.

Firefights with guns, hand-to-hand violence, and real deaths were needed to give unions the leverage they had.

For some reason this history isn't taught in schools.

Maybe not yours but it was taught at my mediocre public school. We definitely covered Fort Frick, the Pinkertons, the Haymarket bombing, formation of the IWW and AFL-CIO, etc. For some reason people just tend to not pay attention or remember anything from their high school history classes.