becuz it is considered a "Western Noir" and there are only 20+ true ones known. It only had a couple of blemishes on it like calling the sheriff a kid when he is obviously in his thirties. All in all not a bad show.
Time is the only true purgatory.
I noticed that the movie has a noir-like musical accompaniment. And of course being on the run from justice is a typical theme in noir.
The actor who played the 'kid' sheriff had just turned 40 at the time of the movie. And he was 2 years older than the actress who played his 'older sister' according to the story.