If they married for love, and wanted the children they produced by their marriage partners as much as any of us, watched their marriages fail so that they had to face bringing up their child without the partner they had assumed would be there for them, had to carry on working as though these things that shattered their world hadn't happened and then went slightly off course in their lives so that they couldn't be as attentive parents as they might otherwise have been - then we shouldn't be surprised if things sometimes go a bit wrong for the child (and you're assuming the split up of the parents in itself didn't do the child damage anyway).
Parents needs should be factored in as well as children's needs and yet in this foolish rush to consider only the needs of the child we collectively tend to forget that (or maybe its a sentimentalists approach to life, where everyone pretends or is supposed to pretend to be as concerned about other people's children as they would be their own).
I ask "What did the state do when the parents designated as failing were trying to be parents?"
Did the authorities seek to blame the parent or did they ask them why they were not happy, and why they were made to feel they were no longer able to parent maybe, as everyone else appeared to take their role from them?
I hope you appreciate where I'm coming from here - children should be getting told to honour their parents as in the bible in my view, and if that isn't happening or the reverse is happening you won't fix anything (where the parents are decent people doing their best of course).
All the best, Graham