So they don’t starve to death is the answer. I EBF one of my dc and the other I had to feed formula because she could not feed from the breast and I couldn’t express enough for her to eat. She was classed a failure to thrive because she lost so much weight. I’m very happy with that decision, even when it wasn’t what I’d hoped for.
The nutritional milks and feeds that a family member with a severe disability are tube fed are also UFPs, but they’ve kept him alive for 15 years when 50 years ago before we had that science, he would have died as a baby. I’m sure his mum would love him to be eating chia pudding with organic fruit and grass fed beef, but this is life. I’m very grateful that the science around formula is what it is today, because when I needed it, it kept my baby alive.
That said, you sound a bit like my friend, the breastfeeding Nazi, as I call her. She thinks that babies should be removed by SS if their mothers choose not to BF them…and placed with families who will, presumably, formula feed them. Boggles the mind really.