I think it is more than that though. Parenthood is a long, multi-year process full of hormones, self-reflection, and fundamental changes to your psyche. A non-parent can intellectually understand what happens and why, can emotionally understand or feel that love by swapping out kids with partners, pets, etc. But I believe there is a level of understanding that is just not possible unless you also go through that process. Hard to describe. Closest analog I can think of right now is my perspective on pregnancy vs my wife's.