“parents want more of this wonderful experience, not less”
Perhaps. But I see this as being in the same boat as a father telling his daughter, I love you, and in the next breath saying, “but if only I had a son” (And yes, I have heard that)
Or telling your spouse, “You’re terrific, but if only I had a 2nd one, our life together would be so much better, so much more complete.”
By saying you want more (over, and over again) the message is, what I have now is nice, but not enough.
Now, of course, I would never say this to a single person, nor to someone (hashem yirachem) that has not yet had children. For them, there is nothing but tefilos and shared pain.
But the implied pressure to have more that can be counted on one hand, and if you don’t you are somehow not living a meaningful life, that’s hurtful too. Perhaps not in the same way, but hurtful none the less.