They could witness a close friend or sibling struggling to raise children.
They could simply reason about the commitment of time and money required and take note of all the other things in life that parenthood would require them to give up.
You can hear about the experience of a POW, but it won't ever be the same as being a POW. Not trying to equate the two, just showing how telling/imagining aren't quite the same as experiencing.
Sure, but that's true for everything, there's nothing unique about parenting here. I.e., you similarly don't have quite the same experience as a no-kids person who has depression.
Yet this argument seems to come exclusively from parents, assigning parenthood a special status, which makes no sense, since parenting is extremely commom.
This is the same argument as “men will never understand women because to truly understand a woman, you have to be a woman” Well, empathy is quite a real thing. Also everyone’s experience is different, so even if you are a woman, you “truly don’t know what it means to be a woman”.
Once you're arguing the philosophy of knowing something as learned knowledge versus personal experience, the discussion has kind of gone off the rails.