On the face of it, I would say she meant to point out that you react stronger to your mother than you do to your father. I'm assuming she said that because she's witnessed more extreme reactions around the topic of her?
she's really the best one to ask though.
Fwiw, sometimes it's hard to see the parent we viewed as "safer" growing up with a new perspective later on when other understanding comes to light. I have always viewed my father as the abusive one. He was always loudest and most obvious about it. Lately though, living with my mom again, I'm seeing the more subtle abuse from her. It's difficult to accept because my belief that she was safer was what kept me going as a kid. Now I just see they are both really broken and damaged by life... neither is really safe. They're just reacting to life how they always have.
It's a ****** realization...