There will never be an answer to this.
You could say poor people shouldn't have children. How is that enforced?
Do we penalise GGG with her five starving children and false nails before we tear into HHH, the elderly vulnerable man who lost his wife and spends every penny on feeding his dog. Who used to manage but his child moved abroad and the government cut his allowance.
Or do we start with those who have had children removed, but pets left in squalor.
What about a down the street who drowned a litter of kittens she couldn't sell.
Then there is B. B feeds the neighbours cats. Often goes without herself, but the neighbours are drug dealers.
It's just a ridiculous assumption that those with pets who care for them should not be allowed them.
I think in Mumsnet there is often a tendency to sweep and say these things.
The reality is there are horrific wrongs across all levels of society, some that should not be justified.
Some that are very much at the heart of poverty that people just will never understand. Eg a charity where they simply cannot take anymore animals, but can help others care for them to give them joy, save shelter in staff and ease that burden.