Having children for financial benefits is a real thing.
It's not just something people accuse the poor of for the purpose of hate (although it is commonly used in such a way).
It's usually not as direct as "let me have this kid so I can get my rebate check", but it's certainly a consideration for many people who are poor. The mentality is more along the lines of "I can't make it by myself, but as a family, we might be able to sustain ourselves".
Most people are aware that it will probably end up costing them more in the long run, but people do crazy things in desperate times.