In the 19th century sword and gun duel were not that rare, think about Mathematician’s Gallois death for example, it seems to be a thing of the past as the last duel occurred in the late 60’s.
Politics also used to be pretty violent, with fascist leagues in the 30’s and even after the war tons of pretty violent fight between political activist in the 60’s and various armed group including full terrorist groups (RAF, ETA and more).
Without saying that today world is peaceful and today politics is “nice diplomacy” things seems pretty laid back simply compared to our parent era and let alone the 19th century.
I would have expected that people would take advantage of modern medicine to be more violent. A duel, or a street fight between political opponent would be way more survivable than it was 100 years ago, so how comes these stuff seems mostly from the past ?
Threat assessment, in a nutshell. Back then you could be relatively sure you were evaluating the threat level of any encounter fairly accurately. You could tell if your target was far more privileged than you, deadly weapons were reasonably obvious. These days you have no way of knowing whether your target has immediate access to deadly weaponry, an unseen group of potential reinforcements via socials, or if law enforcement will be able to investigate and prosecute your actions whether there are witnesses or not.
Clarifying edit: I answered in the spirit of speculation, allowing the premise for the sake of conversation.