i defend the grandmother, the problem here that people forget, is that the ebisumori is not just the main branch family with mutsu, nana, yoshie, mirai and kaya, there are other branch of the family too that compose the whole clan, so potentially there intern politic that need to be take into account, worse, it's a religious cult, that mean there fanatical people that need to run the whole thing.
potentially that can explain the attitude of mutsu with her daughter, so secretive, like she doesn't want to be direct with her daughter, want that her daughter is the one taking the decision of her own vaulition and avoid to be the one making the decision.
if as the head of the family she say that the whole cursed womb need to stop, i will not be surprise if there will be riot in the clan, because it's a really powerfull weapon of mass murder and other branch member can take that as a motive to make a coup d'etat.
another thing, the shocked face that mutsu do in the page 6 of the chapter, she seem to be shocked, surprise to see the remain of her sister, like she was not aware that her sister became a cursed womb, worse from the precedent page 5, she seem to be near her when she explode as nana ask her what happening :
"mom"
"wh"
"what's going on ?"
"please"
remember that mutsu let's her childs near yoshie when she is literraly a tickling bomb that will explode, and mutsu is shown to be a loving mother, as a parent, do you really wish that your child is near a women that will explode into gore mess as in the page 6 ?
i doubt it, especially with a women that chose to not brainwash her child as noticed by yoshie in her journal.
that mean someone else ordonned yoshie to become a cursed womb, someone that has enought power to bypass the great prietress of the ebisumori and keep her in the dark, and that tell a lot.
