Given the cost of childcare it's certainly an easy choice for many low income parents. It costs tens of thousands per kid per year - frequently more than these people even take home for that years work.

At the end of the day, you and I will pay for these kids, it's just a choice of upstream by subsidizing childcare, or downstream by subsidizing all the issues resulting from absent parents and inadequate support. It's literally cheaper to support daycare than not, similar to how preventative healthcare is cheaper than responsive healthcare.

Edit - and if you're expecting people to stop having kids, that's just completely unrealistic