The Man who Turned into A Stick is a difficult play to understand, so I sympathize with you!
The Man and Woman from Hell aren't necessarily bad people, they are people who do what they are supposed to. In fact in the end of the play, when the Man from Hell calls the audiences sticks he says, "‘‘It’s just the simple truth,’’ he says, ‘‘the truth as I see it.’’ Man from Hell represents bureaucracy and the status quo.
IN fact, the woman from hell says that she feels sorry for the stick, the Woman from Hell is comforting for the stick. As characters that are supposed to come from hell, the man and Woman from Hell are not evil, they are fulfilling their duty. Although the Woman from hell is supposed to be emotionless, she is in training and clearly has not gotten their yet.
The man and Woman from hell are not good people, but since they have to be trained to be unemotional its clear that at some point they had normal human emotions.