Minnie Wright is treated like the caged bird: she is imprisoned and isolated in a marriage, the subject of her husband's verbal and emotional abuse.
John Wright treats his wife like a domestic servant. Her role is confined to the kitchen. She used to sing (like a bird) in the church choir, but John doesn't want her away from her duties; he wishes to cut her off from the community of women. He won't even let her have access to a recent invention, the telephone.
The couple has no children, no friends. Minnie Wright has transformed into a slave through neglect and psychological torture. She has no voice, very few rights, and fewer choices; she might as well be in prison, as her home has become one. So she murders her husband in bed as revenge.
The previous post captured much of the condition of Minnie Wright. It is interesting to note how Mrs. Hale is perceived when she tries to piece together her own version of the crime. The male detectives discredit and dismiss her efforts as a "trifle," because a woman could not be smart enough to assemble the elements of a crime. The male detectives use the issue of gender to deny much in terms of women intelligence. It is worthy to note that Mrs. Hale and Mrs. Peters engage in as much in terms of questioning and deductive reasoning to assemble the conditions of the crime in a more scientific and more logical way than the men do. It is why the crime is solved by the women well before the men have figured it out. In this setting, one sees how women were treated and why it is wrong to embody such beliefs towards women. Glaspell's own experiences as a court reporter, no doubt, must have played some role in this rendering.