In "A Jury of Her Peers," why don't the women tell the men what they've found out?

Mrs. Hale and Mrs. Peters each have a personal reason for not turning over the evidence to the attorney and sheriff, and they have one reason that they share. Once the women discover the bent bird cage and the strangled bird, they no longer entertain any doubts that Mrs. Wright killed her husband. However, Mrs. Hale, rather than blaming the former Minnie Foster for her actions, blames herself for her own role in the situation. She recriminates herself, saying she should have visited Minnie at her home and should have picked up on the isolated and soul-killing atmosphere Mr. Wright forced on his wife. When the awfulness of Mrs. Wright's lonely and oppressed existence fully dawns on Mrs. Hale, she cries out, "Oh, I wish I'd come over here once in a while! ... That was a crime! Who's going to punish that?"

Mrs. Peters gains insight into Mrs. Wright, a woman she didn't know previously, by contemplating what it would have been like to have been childless, enjoy the pleasure of a song bird for a while, and then have the bird brutally killed. Mrs. Peters recalls a bully having killed her cat with a hatchet when she was little. She says, "If they hadn't held me back I would have ... hurt him." She also thinks about how still her house was after she lost her oldest child. Both these situations allow Mrs. Peters to empathize with Mrs. Wright.

Though each woman has a personal reason for sympathizing with Mrs. Wright, those reasons alone may not have been enough for them to withhold the evidence from the men. Ironically, however, the men's own condescension towards Mrs. Hale and Mrs. Peters gives them the additional motivation they need to keep their findings secret. Throughout the story the men, especially the county attorney and the sheriff, mock and belittle the two women and all of their gender. They criticize Mrs. Wright's housekeeping, they scoff at the women's concern for "trifles," patronize "the ladies," and repeatedly laugh about the women's interest in whether Mrs. Wright planned to knot or quilt the squares. The women bear with those remarks; certainly, they hear them on a regular basis and barely bother letting such remarks offend them. Nevertheless, they know that when Mrs. Wright comes to trial, it will not be before a jury of her peers because women did not serve on juries then. Twelve men with the same lack of empathy and the same condescension for women will determine Mrs. Wright's fate. No doubt Mrs. Peters and Mrs. Hale do not think that Mrs. Wright was fully justified in her actions. Yet they know that she will be at the mercy of the mocking county attorney: "Mr. Henderson is awful sarcastic in a speech, and he's going to make fun of her" Mrs. Peters notes early in the story.

Because they know Mrs. Wright will not receive a trial that will take into consideration all the backstory that the women have reconstructed, they can't bring themselves to subject her to more unfair treatment at the hands of the law. Therefore they decide to act as a jury of her peers, doing what they can to assure that she gets a lighter sentence or no sentence at all.