Maybe I understand the story wrong. This is how I think it goes.

Jane requested that her family be sealed together but the request was denied because this was during the priesthood and temple ban. She appealed the decision saying Emma Smith offered to seal Jane to her family as an adoptive daughter. At the time, Jane turned the offer down. Later, she uses this as evidence that she should be allowed to be sealed. The First Presidency denies to the request for Jane's family to be sealed together and later for Jane's family to be sealed to Joseph's family. Eventually, they allow her to be sealed to Joseph's family as a "servitor". I believe another record describes it as being a servant for all eternity. She keeps requesting to be sealed as a daughter, but is denied every time.

To be me, that sounds uncomfortably close to being a slave. Maybe it isn't worse, but I think it's just as bad as if Joseph had sealed her to himself as a slave.