Nah. It comes from a real worry about the future.

The OP left a few important considerations out of the argument. It's not just about food. It's also about energy and equity. Most of the protonatalists do not support policies that alleviate the burden of raising a child. They just want the babies so they'll have a cushy old age and shame women to have them. They also refuse to restructure work (and they're the CEOs so they could) in order to make child care more manageable for women. Apparently they think you can just stuff the babies in a closet when it's time to go to work.

So they're not willing to put their money and political influence where their mouths are. They're just adding more work to women who are already disproportionately overburdened.

It's clear what they really want is for all the hardship to fall on women and children rather than their old age.

If we're going to have this conversation and make it a moral one, let's talk about the morality or lack thereof of artificially extending the lives of the wealthy ages amongst us by further disenfranchising the young and unborn. Why can't we just let them die? Then there'll be more resources for the rest of us. Maybe if they wanted a long life, they should have lived better?