Why was cross-dressing the only crime Joan of Arc was charged with?

Joan of Arc's Divine Mission

England and France fought for the French throne during the Hundred Years War.
England and France fought for the French throne during the Hundred Years War.

By 1429, the English occupied the northern French provinces of Normandy and Brittany. Burgundy, on the eastern border of France, remained independent but allied with England, effectively pressuring French forces on nearly all sides. Charles VII, the French dauphin (heir to the throne) lived in exile in the Chinon court deep in France's western territory.

At the age of 16, Joan of Arc set out to meet the exiled dauphin in Chinon. Three years earlier, she began hearing voices one day while working outdoors at her home in Domrémy in Champagne region. She identified them as belonging to St. Michael, St. Margaret and St. Catharine. At first, the trio of saints encouraged her in simple things, such as being a good daughter. But then, the messages intensified. They directed Joan to cut her hair short and don men's clothing in order to meet the dauphin and eventually lead the French to victory over the English, bringing Charles VII to the throne. Joan of Arc's father even had dreams of her surrounded by soldiers and urged her brothers to keep their sister from running away.

Joan didn't heed her father's wishes and set out for the dauphin's court with a newly cropped hairdo and an unwavering belief that she was sent by God to put the rightful king on the throne of France. Not surprisingly, the 16-year-old cross-dressing girl's arrival in Chinon didn't go unnoticed. Two days after requesting to meet with Charles, Joan of Arc was granted permission to hold court with the dauphin.

When Joan of Arc arrived to meet him, Charles intentionally hid among the crowd of nobility in the hall. Nevertheless, the 16-year-old recognized him immediately. After a brief, private conversation, Charles announced that he trusted Joan of Arc's divine mission since she was able to tell him a secret about himself that no one else could possibly know (which remains unknown to this day). To ensure that he wasn't about to hand over the fate of France to a soothsayer or witch, Charles sent Joan to be examined by a panel of clerics. They agreed with the dauphin that Joan of Arc had, indeed, heard the word of God. With that, Joan of Arc became a captain in the French military and prepared to rescue the city of Orléans from English occupation.