Snow has always been a compassionate woman. She was a compassionate child who could not sacrifice a stranger for her mother. She was a compassionate woman who rescued a stranger from execution and later chose to let Regina live rather than murder her for all to see. She has been compassionate at nearly every turn (except that time she murdered Cora–shhh). What Snow has NEVER been is empathetic. She has compassion but never understanding. It’s the key difference in her relationship with Regina versus Emma’s relationship with Regina. Emma “gets” Regina because she’s been the abused kid and the angry adult and she’s had the whole world hate her. Snow never has. She never had to learn empathy the way Emma has.