I think a major factor in this country having less mass shootings in the old days is that those freaks could fulfill their homicidal tendencies by participating in lynchings or by murdering other people, whether they were Native Americans or even other white people, in the American frontier.

Lynch mobs had participants who were verifiably not normal people.

The man who drove Leo Frank to the tree where he was lynched was executed in Louisiana in 1935 for raping and nearly decapitating a 16-year-old girl after escaping from prison in Georgia, where he was serving a life sentence for child rape. The man, D.B. Napier, revealed his true identity after the police saved him from being lynched.