I disagree with your interpretation that "if you need public assistance, stop fucking" actually means "if you're rich, have all the kids you want" because we're not seeing that. Among the richer nations, birth rate is decreasing.

It may be an unpleasant thought, but it goes along with "if you find yourself in a hole, stop digging". If you need help to feed the children you have, you shouldn't have any more and make the problem worse. As to fixing the problem, the areas of the world facing starvation and high child mortality rates ARE the poor areas because they're making more kids than they could feed. Reduce the number of pregnancies and the starvation problem will get better in a few years.

Remember, with freedom comes responsibility.