When you have no job stability, or you yourself suffer severe depression, or you’re just poor and have no means or support network, then having kids is insanely stressful way way way beyond the kind of yuppie parents-who-think-not-sleeping-is-stress lightweight stuff.
Kids, like houses, vacations, fancy university degrees and adequate medical care, are something only accessible to rich people (and triggers a knee-jerk reaction in such people to try to argue they aren’t rich with ineffective anecdata and arbitrary thresholds).