I do pay tax you know. Quite a lot of it. But tax is NOT just money that is earned. That is simply one type of tax - two if you count NI. And as I'm sure you know, people on low incomes actually receive more back in tax credits than they pay - but then I suppose they're scrounging as well?
Tax is duty on fuel, alcohol and cigarettes, VAT on goods, inheritance tax, corporation tax, pension funds tax, etc. etc. People who work to earn money, and earn enough to pay income tax, do not have a monopoly on paying tax.
If someone goes out to work and manages to find a minimum wage job that pays say £10k a year. They could easily receive £7k a year from the taxpayer to pay for full time childcare. Plus other tax credits, housing benefit, etc. That's probably as much, if not more, than they are already receiving in benefits.
There are many reasons for going out to work, don't get me wrong. But doing it for the good of "the taxpayer" is not one of them.