Everytime I have seen this situation (eg unexplained anger while nursing)
there has been a sexual abuse history. Obviously no one should force this
mother to nurse, however the deeper issue of abuse, if it indeed exists,
should be professionally  addresssed. She may not be *aware* that she was
abused. Her anger may not be at the baby but at the abuser. The situation is
too close to something that happened in her history.
I had one mom who kept referring to one of her breasts as the bad one. When I
questioned her regarding why it was bad she told me "that's the breast  he
always grabbed when..." and recieved a barrage of sexual abuse hisory. I got
her in for counciling and she did well.
I have also met mothers who want to give their babies breastmilk but do not
want to put the baby to breast. In each case there was a history of childhood
sexual abuse. As an LC I worked at helping the mothers with  longterm pumping
and encouraged them to seek professional help to resolve the sexual abuse
issues.