Stephen Crane believed in making his message explicit. According to his friend Herbert P. Williams, "He does not think to trust the imagination of any one who reads."
Trust their imagination? Why, they haven't got any! They are used to having everything detailed for them. Our imaginations are defunct for lack of use, like our noses. So whether I say a thing or suggest it, I try to put it in the most forcible way.--Stephen Crane
Crane puts his message in the mouth of the Easterner, who was present when the Swede got into a fight with Johnnie, the hotel owner's son, over a card game. The Easterner encounters the cowboy who was also present during the quarrel and the fist fight which led indirectly to the Swede getting killed by the gambler in the saloon. This is Crane's message as spoken by the Easterner to the cowboy in a cabin on the Dakota line some months after the Swede was killed and the gambler was sentenced to three years in prison for the crime.
"Fun or not," said the Easterner. "Johnnie was cheating. I saw him. I know it. I saw him. And I refused to stand up and be a man. I let the Swede fight it out alone. And you--you were simply puffing around the place and wanting to fight. And then old Scully himself! We were all in it! This poor gambler isn't even a noun. He is a kind of an adverb. Every sin is the result of a collaboration. We, five of us, have collaborated in the murder of this Swede. Usually there are from a dozen to forty women really involved in every murder, but in this case it seems to be only five men--you, I, Johnnie, old Scully; and that fool of an unfortunate gambler came merely as a culmination, the apex of a human movement, and gets all the punishment.
I have italicized "Every sin is the result of a collaboration" because that sentence capsulizes the meaning of "The Blue Hotel" and Stephen Crane's philosophy. Crane seems to believe that life is an endless chain of cause and effect, one thing leading to another. For example: the Swede was feeling cocky because he had beaten Johnnie in a fight, and this led to his assaulting the gambler, which led to the gambler killing him with a knife, which in turn led to the gambler being sent to prison. Crane's story suggests that the death of the Swede was inevitable from the time he arrived at the Blue Hotel in Fort Romper because of an unbreakable chain of cause and effect.
I would love to answer you but I do not know about the story your asking about because you did not list it.