These are questions that push you into the herd or nip at you for diverging from it, questions that contain their own answers and whose aim is enforcement and punishment.
Humanity, society, is a complex and well-built machine. Humans, our actions, our attitudes, our assumptions, are not all too unlike bugs that we talk about having a "hive mind". People don't hesitate to push each other into line, to attack, to ask questions, and so on, because these questions, the mindsets that lead to people asking them, are questions that resulted in a better human that worked better and reproduced more.
You see it everywhere, from our attitudes about self sacrifice, how we are "imprinted" onto this idea of doing everything for ones family, to die for your nation. Our very sense of emotion, outrage, anger, is often twisted to serve the larger whole rather than ourselves. We seek to help others, especially those portrayed by society as needing help, over ourselves.
And to not do so is bad, so if you don't, you become selfish, greedy, out of line, and must be corrected.
Society needs kids. It needs people to have them, to believe that having kids is for the best, that the "happy moments" are worth it. As the article mentions, fuck that. The most I see of kids is people who forgot to use birth control and screwed up, or didn't have a grasp on just how hard a kid is to raise in the first place.
And society can, and will, pull out all the stops to get you to fall into the trap of thinking "this is good for me". Emotional attachment, showing kids in media as small, innocent, cute, nice, never mean evil or failures. Expecting people to have kids, to have a culture where not to have them is odd, strange, stupid, selfish, evil almost.
My mom does it, a combination of "I want grandkids", never said directly, but implied, and "you'll want kids eventually".
Meanwhile I have been doing my best to not so much as consider dating, to consider marriage, to consider any level of beyond-friendship interaction with anyone of the opposite sex, because, like all other things, dating is "designed" to pull you in, to get you to date, closer to that all important moment of reproduction. First you "just want to date" then "I want to spend my whole life with this person" then it's either "forgot to use a condom" or "oh, babies are just so cute". A slippery slope, I believe. Eventually one of you realizes the love is gone and leaves or sticks around until death, likely hurting the other in doing so.
It's not wrong, of course, for people to say this, to act like this. After all, without it, we wouldn't be here. In some ways, to refuse to have kids for your own sake is selfish, it is something that would kill society off if everyone went and looked for their own benefit.
It's not particularly right either, to force people into a life they don't want, to brainwash people for the sake of the greater good.
At the end of the day, it just is. Balance will have be found between what has to be done, and what should be done, and I imagine that balance will be found through more emotional discourse, with the side who has the closest "disaster" getting the emotional upper hand until they cause a disaster of their own, and the cycle repeats.