My wife couldn't produce milk. My wife's niece wouldn't latch. There are a lot of people in these situations where, even if true, your reasoning does not apply.
I wasn't actually making an argument beyond what I posted; if I was to provide an explanation of its relevance it is that it is a fairly common position that real and relevant differences are a necessary, but not necessarily, sufficient condition for policy distinctions, and that insofar as the subthread on the advantages of being with the mother was relevant to the broader subject to start with, it remained relevant (though not, in and of itself, demanding any particular conclusion) as long as there was a real, on-average difference.
Beyond that, if you adopt a policy that considers these outliers and normalize parental leave, there will be parents where breastfeeding is possible but the fathers still take the parental leave.
A young child will be nursing many times during a day, giving plenty of opportunities for a working mother to nurse their child without giving up time to work on their career. Feedings while the mother is out can be done by bottle using pumped milk, or through formula.
Sexual differences do not need to imply social advantage/disadvantage here ...