1. "Should": This implies a right and a wrong, or at least a better and a worse. Anybody talking "shoulds" ought to be able to elaborate on just where those "shoulds" comes from. Out of the heads of celebrities who have a series on Netflix? Natural law? Religious dogma? Conventional wisdom? Gallup?
2. "We": Hold up a minute--who's "we"? Presumably it's a pretty big "we," with power to create "policies" that govern the whole "developed world." Whoever "we" is, it's somebody more powerful than a president or a prime minister, and "we" will be needing enforcement mechanisms with some kind of teeth if "we" want to see policies with real-world results. "Our" teeth will have to be not only broad, but also long--long enough to bite deep into the most intimate decisions of each of those millions of "developed-world people."
3. "Have policies": Well, let's be candid, Bill. Do "we" mean "have policies" or "enforce policies"? See no. 2.
4. "That penalize people": This raises an interesting question. What level of penalty are "we" talking here? If what's at stake is "saving the world," it's probably one that will make people sit up and take notice. More on the level of a Little Sisters of the Poor fine than a traffic ticket.
5."For having": Well, but some people "have" children because they're doing what comes naturally and a child results. Some have them because they're timing what comes naturally in hopes that a child will result. But others have them because their contraception failed, and some of those failures are due to carelessness, others to a defect or limitation of the method that was supposed to prevent the children's existence. Some women are raped or otherwise coerced into pregnancy. When "we" devise these "policies" that "penalize people," are we going to run roughshod over such distinctions? Or are we going to have to devise a bunch of sub-policies to see that the heaviest penalties fall on the ones who actually wanted their children to be born? This seems only fair, right?
6. "Extra kids": Whoa, wait a minute. Let's think this out. The question is not just "Who counts as extra?" It's not just, "How can you, Bill Nye, be so very sure you're not one of the extras?" It's also: "On what grounds are you assuming that there's a distinction to be made between 'extra kids' and...what? High-quality kids? Fit kids? Essential kids?" Who in the hell are you to decide such things?
7. "In the developed world": Here, and here alone, does a reasonable person find a little, little something with the teensiest, weensiest grain of truth. Here we see the merest hint of reluctance to blame people in the undeveloped world for having all the "extra" children, the slightest hesitance to "save the world" by picking on precisely the parents who have more troubles than everybody else already. Good for you, Bill. I always like to end on a positive note, and look! I found one! Even in the pile of dreck you tried to pass off as the innocent question of a Science Guy.