I do believe, expect in special circumstances of abuse, that both parents should be fully involved in the upbringing of their children, whether married or not. If marriage helps parents to remain committed to their children, then it should be encouraged and promoted as the ideal. But I suppose marriage isn't really the issue, it's just that people shouldn't have children if they are going to abandon or neglect them or use them as weapons to hurt an ex-partner. It just seems common sense that it is better for a child and for its parents if there are two of them to do the work and provide the care. But it is a generalisation and, when all is said and done, I don't think it's possible to argue convincingly that single parents are better than 2-parent families or vice versa. As Nutcracker said, it depends on the individuals doing the parenting. It's not the point and it doesn't help anyone.
But I do totally share the OP's frustration at the way the media reports the subject of single parent families - as if we are the dregs and the rot of society - as if we cannot possibly do as good a job as a 2-parent family. Is it any wonder that we feel defensive about it? The way the issues are presented in the media isn't helpful, it's just divisive and it warps the public's perception of single parents which could in turn affect children in single-parent families, cause bullying perhaps.
The current tax credit system does seem to benefit single parent households and being able to have working tax credit for working only 16 hours is direct discrimination in favour of single parents. I can understand why some 2-parent families where both parents are working full-time, but who still have low income, might feel that it is unfair - might think that single parents get to work part-time and see more of their kids, whereas they have to slog away at full time jobs and only see their kids at weekends. I understand they might have this perception - BUT - I still think it is probably, on average, incorrect. BECAUSE, the practical, emotional and financial disadvantages and difficulties of being in a single parent family probably still outweigh any small advantage that the tax credit system gives them. And the fact that single parent families tend to be amongst those receiving tax credits speaks for itself, they are the families with low income and the system is designed to help them because they have low income, not because they are single parents. The little extra money still does not make up for the fact that it is bloody hard being a single parent and the additional practical difficulties that it involves but it might help with contingencies such as paying for a child-minder when a child is sick and the mother has to work, when the second parent, the father, just isn't there and can't fill in.
Or don't we want a welfare state any more? Don't we care about all children, not just our own? I'm all right Jack, sod you? It's your fault that your relationship with the father failed. It would never happen to me....until it does, because it can happen to anyone.
In an ideal world, any government policy or system should treat everyone equally, regardless of who they are and what their status is but this is never possible as everyone's circumstances are different and it is never the case that one size fits all. Think of all those billionaires who never pay any tax at all because they have clever accountants.
You could have a single mother who got to keep the 4 bedroom house, who recieves £600 per month maintenance, who works 16 hours and receives child and working tax credit - who works part-time and is also pretty well-off financially in her own right. She might also have a good relationship with her generous and kind xh (they just 'grew apart')and extended family, all willing to help out if she fancies going off on a spa weekend with her best mate. Does she really need or deserve the tax credits?
Or you could have a single mother whose xh is a complete violent bastard who terrorises her and their children. He doesn't give her any maintenance. Or maybe he died and she's a widow. She has no family to help her and never gets any time to herself. She has no qualifications to get a decent job. She has no car and so is restricted with regard to the jobs she could take. Her children are traumatised and one has special needs so needs extra care. She is suffering from exhaustion and is depressed. They are living in a damp flat and can't afford to replace the broken washing machine so she has to trog to the launderette with the kids in tow. Ok, I'm getting carried away with my imagination here - a bit ridiculous - but there are people living with these circumstances and don't they deserve the little extra help that tax credits give them?
The government doesn't have the resources to assess everyone individually to see if their particular circumstances merit additional financial support. The government has to come up with a general policy in the hope that those who really need the extra help will get it. If there are some 2-parent families who are also struggling unfairly, the government should try to tweak the system to correct this. Maybe the DC policy would do that but I don't know.
In the end, the system can never be completely fair, for the reasons stated above, but, in this day and age, with so many single parent families, the politicians and media should handle the issue more responsibly such that it is not touted as a policy for married parents or a policy for single parents which can only have the effect of causing, possibly or probably false, divisions and prejudice between different types of families.
I think there should be some kind of carer's wage for mothers (single or married) who want to stay at home to look after their children. It shouldn't be a lot (so that it is not an incentive to stay at home) and it should only be available for mothers of children below school age. Or there should be a reduced amount for mothers who are still not working when their children are at school but who have special circumstances, e.g. lots of children or children with special needs which make it more difficult for them to work and still be there for their family needs. But I suppose the tax credit system already caters for these circumstances. Is anything further needed?
As someone else has said, I think saying that all mothers of children aged 11 and above should work full-time could have the effect of creating latch-key kids because not everyone can or is going to pay for after-school club or a child-minder. And there is the other issue that, as a generalisation, parents who live together can take it in turns to take time off work for sports days, children's illnesses, emergencies whereas single parents might have noone to share these responsibilities with. This perception may not be entirely accurate (e.g. a single parent may have family who will help) but nonetheless single parents tend to be seen as a bit of a liability by employers which makes it harder for single parents to gain employment even if they want to work. This is probably why, in their wisdom, the government saw fit to allow the dispensation to single parents of qualifying for working tax credit while only working 16 hours instead of 30.