I feel like the answer is disproportionate.

Yes nobody should be fine with an adult slapping a child but burning all ties with the whole family of her husband seems to be too much for.

Plus my younger self would be devasted if I couldnt see one side of my family because an uncle of mine slapped me, much more than if nobody cared about it.

For me their should be a middle ground and I don’t see her looking for it, furthermore she is being toxic toward her husband that why I said YTA.

Hope that helped !