I am biased, one of my best friends is the last child of a very large family (think six children, I tend to forget the exact number) and while they were all fed and clothed, money was tight. I am of the opinion that her parents were right to have so many children.
Anyway, I don't think it is fair to want to tell the "working poor" how many children to have. They are working. It is not their fault that they don't earn the same money other working people do.
And for unemployed people, likely one or two children are "too many" to afford, yet women are told to have children before 35, and biology doesn't exactly wait until you managed to get a job, either.
Since I live in a country (and I think the UK is such a country, too) where the elderly are paid out their pensions out of the money the younger generation pays into the insurances, everyone profits when children are born, so it is only fair that everyone pays for it.
There is of course people who bring up their children to be useless little shits, but it's not fair to punish all poor people for those few bad eggs.
It falls to women because they ultimately have the choice how many children they have
Um, no?
True, men (in a healthy, equal relationship, that is, there's enough men who commit reproductive coercion) don't have a choice when it comes to having more children, but if we are going to criticise people for having too many children, then men are just as responsible for that. Men can choose to stop fathering children at any point in time.