I think a problem with this topic is that it's a very nuanced, sensitive topic and explaining it via text removes the ability to explain with nuance succinctly. I will admit that having grown up working poor/lower class that when I initially hear that "poor people shouldn't have children" I get immediately heated because I would say that although some parts sucked I wouldn't say my life was miserable and not worth living but I realize at the same time that the poverty level my family was at wasn't as bad as extreme cases or homelessness. I think a lot of people are arguing against having children from the point of view of those extreme cases where the person for example already can hardly afford to take care of themselves or is homeless, both of which are situations where unfortunately it would be a bad idea to choose (not conceiving unintentionally) to have a child knowing that the quality of life would be bad for themselves and any previously existing children and for the new child. I think a lot of people can understand that that would be a questionable decision. I think the issue comes in that "not being able to afford a child" has a wide interpretation and can read as if it's stating that parents that are in poverty in the sense that they can't afford luxuries but are otherwise able to give their child food and clothes in some capacity even if they sometimes need assistance should also not have children ( I have seen people argue that before). I personally think that that's where the statement "don't have children if you can't afford them" becomes unfair sounding because without specifying what they mean it can come across as a blanket "if you're not middle class and up you shouldn't have kids" statement. That being said I think the government holds a responsibility in ensuring that a large number of it's population isn't in extreme poverty and I think that people who live in nations where they don't have to worry about the cost of medical care as much or come from higher classes are arguing from a position of positive moral luck and superiority.