I thought this was a pretty bad look: Mountain Meadows Massacre

The Mountain Meadows Massacre (September 7–11, 1857) was a series of attacks during the Utah War that resulted in the mass murder of at least 120 members of the Baker–Fancher emigrant wagon train.

Even there, they try to throw you off because it had nothing to do with the Utah War. This was just a wagon train of emigrants passing through. It's pretty gross when you read the full story, including lowlights like: false flag trying to pin it on Indians, theft, execution under a white flag of truce, and kidnapping.

It's almost unbelievable now, but many years ago I just stumbled into a docu-drama they made about it on Netflix. In probably 10-12 years since, I have never seen this incident mentioned a single other time.