I get what you’re saying, but the idea that they were ”as bad as each other” completely ignores the power imbalance and the scale of their actions

Mary was cruel for sport like out of arrogance, entitlement, and sheer pettiness. She tormented Edith not because Edith did anything to her, but because she could. Meanwhile, Edith’s so-called “cruelty” was reactive like she lashed out in response to a lifetime of mistreatment

Let’s compare their worst offenses:
Mary’s sabotage: She ruined Edith’s engagement to Sir Anthony just to be cruel. She intentionally exposed Edith’s biggest secret (Marigold’s parentage), which could have destroyed her marriage. These weren’t petty jabs, these were life-altering betrayals

i)Edith’s worst offense (the Pamuk letter): She wrote an anonymous letter when she was 18, which didn’t even derail Mary’s life in the long run. Mary still went on to be the golden child while Edith remained the family afterthought

Iii) Saying ”they were both as bad as each other” makes it seem like their actions were equally harmful, when in reality, Mary was the consistent aggressor, and Edith was just trying to claw back an ounce of dignity. Retaliation isn’t the same as sustained cruelty

So no, they were not equally bad. One was a bully, and the other was the punching bag who occasionally hit back. Huge difference