The stone was not the punishment
Ahalya's story in the Valmiki Ramayana begins, for most readers, with a curse. Gautama Maharishi discovers the deception, speaks the words, and she becomes stone. That is the image that lodges: a woman frozen, abandoned in her own ashram, waiting for a god's foot to cross her threshold and restore her. The reading that follows from this image is a passive one. She is wronged. She waits. She is saved.