Why do we deserve to know the reason?
I don't think anybody on these board are entitled to a reason. That said it is human nature to question why a skater has done so terribly to epic proportions.
Though she should have said it much earlier and notified USFSA, at least Rachael did disclose her injury and people could say, "ah that's why." Alissa and Alissa's team have been quite mysterious about the general state of her skating. Again, we shouldn't feel entitled for this information, but it's natural for people to wonder.