The plot of "Blazing Saddles" is all about people who are shocked after a black man is appointed as the sheriff in their town.
So, why is the title "Blazing Saddles"?
In the DVD commentary, Mel Brooks said that the working title for the film was "Tex X", as a reference to black Muslim leader Malcolm X. It was then switched to "Black Bart", then to "The Purple Sage". In either case, neither he nor the other writers thought those were great titles. Brooks says that one morning he was taking a shower and the words "Blazing Saddles" suddenly popped into his head. When he got out of the shower, he pitched the title to his wife, actress Anne Bancroft, who liked the idea, and that's how the movie ended up with its title.
I think that “blazing pistols” refers to a sort of film genre.
When Rooster tells the girl about the time he faced down seven horsemen by riding straight at them with blazing pistols, she says "I admire your poise," as though congratulating a ballet dancer.
From a review of True Grit.
Rather than double-crosses and blazing pistols, this film is more about existential yearnings and philosophical debates.
From a review of Hail, Mafia!
And it seems to me that in choosing the title "Blazing Saddles," Brooks was making a joke, directing our attention away from the excitement of a gunfight and to the possibility that when a cowboy gets onto a horse that has been standing in the sun he might find the saddle warm against his backside.