My problem is that at this time of the story, the kids have already been humbleled down, there is no need to make everything you can to destroy the little self esteem they still have unless you need to do so to make yourself feel better.
The story has been clear that they aren't.
I would have been fine with the moms refusing to take them back and force character development on the kids. They have made all they could to be sure the kids had no place to go back to anyway. But if you take them back in and never make anything to help them improve, it means that you enjoy seeing your kids miserable.
Take the case of Lida. I think she's the worst case here, by far. After their defeat against Mamon, she can't even hold a sword without her whole body trembling. What do the mothers and the previous Sword Saint do to have her move on? They fight her 3 VS 1 and beat the crap out of her day in and day out and call that training and laugh at her. I couldn't see that as a "serves you right" scene, it was straight up bullying.
Why not? If you want to show that the mothers are better than the kids, show them being better persons as well. Like I said, they are good wives to Ceres, but terrible mothers to their kids. The kids are not the one who wronged the mothers, it was their husbands. Yet the vengance against the kids is way stronger than what they did to their husbands.
I don't mind the mothers being harsh to their kids. My problem is that it is the only type of interaction they have. They act like they hate their kids, and Ceres never cared about being kicked out anyway. So they don't need to punish the kids on behalf of Ceres.
Then why didn't the mother oppose Ceres's decision to take them back? It's not like they fear to talk back to him. Like I said, you either cut them out and force them to take their own responsibilities. Or you acknowledge that they can't be left alone and that they need help. But if you take them back just as someone to put down to boost your own ego, you're a bad person.