The film's moral perspective

Bit stuffy I just enjoyed the movie.

I find the moral stance of the characters simply unacceptable. Of course, it is a movie and I enjoyed following these reprehensible but strangely likable characters on their arc to destruction.

It was only a film.

The thing is, with the exception of the final scene, "Butch Cassidy" is primarily a light-hearted comedy/adventure movie, with a silly, anachronistic pop-song interlude. A deep examination of the main characters' morality is taking it far too seriously.

"Bonnie and Clyde", however, is different. The film has moments of humor (e.g., the Gene Wilder scene), but is mostly serious and grim. The audience is expected to find Bonnie and Clyde glamorous and romantic, while in reality they were both homicidal psychopath trash. Whatever the real-life and cinematic Butch and Sundance's faults may have been, they were not murderers.

The rip-off of this movie, Alias Smith and Jones, called the protagonists, "pretty good bad guys." They weren't good guys. But they weren't leaving a trail of blood wherever they went, either.

"Then there’s the scene where they kill the bandits trying to steal the payroll, ending with them expressing regret at killing because they’ve gone straight, implying that they were somehow in better shape morally when they were robbing, because they never killed anybody. What nonsense."

It's not nonsense. They most certainly "were somehow in better shape morally" before. Killing is far worse, morally, than robbing without killing.