Well you did say that endometriosis has to be "pretty bad" for a hysterectomy to be a treatment, then adding the "if you want to have more kids"...
Which to me reads as you doubting it was really bad enough to warrant the procedure, as it is rarely needed, and then using that assumption to fuel your argument that if she wanted more children she should have pursued another course of treatment.
My point is simply that in my opinion as we don't know how bad the condition was that it is unfair to assert the argument you're making. My position on such things is generally to assume medical decisions are made with serious thought given to them, and to trust that the patient and doctor made the best choices they could.
However they exactly arrived there Nancy and Thomas came to a point in time where they were married, wished to have children, and Nancy was incapable of doing so, but Thomas wasn't, and he decided to use his female plumbing to achieve what they both wanted. It's all pretty straightforward to me up to that point.
As others have pointed out, the apparent publicity seeking is quite a bit more foggy and I'm not sure how to feel about it.