I don't think it's about 'attacking' anyone - that's very emotive language.
A friend of mine - university educated and well able to work - left her job when she married and never worked again. She has four children, and because of the spacing of them got her NI paid until the youngest was 12 (although having children gave you qualifying years towards a pension until the youngest child was 16 not so long ago. It is relatively recently that this was changed to 12). At this point her husband's accountant advised her to pay a voluntary contribution to ensure that she gets a full pension, which she will soon be entitled to.
How can this be fair, when people who can't afford not to work are paying NI to subsidise her, and others like her, when the workers have to pay for childcare and transport, and all the other things associated with working, and she had none of those costs?
I think there is a difference between people like my friend, and those of earlier generations when the opportunities for women to work were fewer, as childcare was more difficult to find. I grew up in the 60s, and none of my friends' mothers worked, and I don't think there were any nurseries near us at all, so it would have been unfair to penalise them for not working, and to leave them destitute when their husbands died.
As time went by, though, there was nothing stopping those women going to work - by the 80s, the mums who had babies in the late 50s and 60s had years of working life ahead of them, and when their children had grown up there was no reason why they couldn't do it. My mum was 45 when my brother (her youngest) hit 16 - what was stopping her generation from going to work then? 16 year olds can join the army, so surely 12 year olds should be able to let themselves in, make a sandwich and sit in the house for a couple of hours after school? It would have made more sense to pay NI until the youngest child was at school, and then level the playing field so that some women were not given a free pension for decades of not working whilst others subsidised them.
There is definitely no reason why mothers can't go to work now, and hasn't been for years. My first was born in 1990, and by then there were creches and nurseries everywhere. They were expensive, but a bit later the Blair government introduced pre-school nurseries and tax credits for those on lower incomes, to make it easier for parents could afford to work.
Yes, some mothers choose not to work - both now and back then, which is fine, but choices cost money, and I don't think it's reasonable for people to expect others to fund their choices. It's not as though their husbands pay (or paid) extra tax to make up for the loss of theirs, yet grants, benefits, means tests and so on are based on household incomes that don't differentiate between two and one-income families. It's another case where the system works to help those who have more in the first place (and can afford to stay at home) at the expense of those who have to work to pay the bills.