Agree with you translator,
While Revenge for bully might be the best for these type of people but their daughter which entirely different person seems bad idea in general.
Here I thought her mom would just fuck themselves after what she did, so the Sensei took their daughter out of Love after trying to manipulate her because of the pity feeling.
Or
The biggest fuck you ending where the mom during got mindbreak, cuck, bring the shame of her daughter (slut mother, no father etc) to the bullying mother. Later to the point she killed herself leaving her daughter without any guardian.