Ive not read the whole thread, but i can imagine this has kicked off. I think the OP is being slightly obtuse and niave. It is very different being a single mum than a mum with a partner. Often there is no choice about staying at home, it simply would not pay to work. I know this, ive been in that situation.
I can also speak from the couples perspective too. I am a SAHM, our income is tight due to DP struggling business, if i were to work then it would be less tight, but i have chosen and to a certain degree, circumstances have dictated that i am a SAHM. We receive 100 a week in tax credits, so i suppose my decision to stay at home is subsidised and one could argue that i shouldn't be entitled to it.
This point, i feel, totally disqualifies the original argument. Benefits are paid out of need, we, as a couple need more money than DP can bring in so we receive benefits. I am a SAHM, through choice. A single mum needs money to live on, so she gets benefits, she may or may not be a SAHM through choice, but i think that she is as entitled to that choice as someone who happens to have a partner.
Jellybeans, as far as i am aware, subsidised childcare only starts at three years old and only for 2.5 hours a day.
I don't think that being a SAHM automatically entitles you for money from the state if your partner brings home enough. But it IS possible to get help if by making the choice to be a SAHM it puts you under financial strain, there is help out there.