According to Hume, the materialist cannot jump from what is to what ought to be.
"You cannot, according to Hume, derive an “ought” from an “is,” at least without a supporting “ought” premise." So, deciding that you ought not to protect babies in the womb because it inhibits freedom of choice presupposes that causing harm to unborn babies is not wrong or immoral. This presupposition seems good enough for most people in America at present.