Feminists

Most supposedly breastfeeding-friendly laws and cases in the USA are actually negative. They imply very clearly or even may state that women's breasts are indecent, obscene, disorderly, or in other ways harmful, except for breastfeeding. So The Man deigns to allow women to breastfeed, under conditions that he specifies, which often and deliberately make breastfeeding difficult and consequently harm children and women both.

Women are secondary humans and therefore have to be controlled more. They're dangerous and immoral if they're not controlled by men or are allowed ownership of their own bodies.

That may be an exaggeration, but not much of one, and historically that's where much of this comes from.