It is important to note that Rabbi Yitzḥak, like Maimonides and Aristotle, was a product of his time. This argument of course does not necessary support moral relativism. But it does explain the bigger picture, the context of which these people lived. George Washington owned slaves, yes, but that does not make every thing ever he did inadequate. Had Washington lived today he wouldn’t have owned slaves. He was a very honorable man, despite his involvement in the slave trade. In fact, most abolitionist who advocated for the abolition of the slave trade said racist things. For example, they felt that only Europeans could free the Africans. Great men like Thomas Jefferson despised slavery but had no immediate solution to the problem. We can and should understand men like Maimonides or R Yitzhak in the same way. They felt that women were less educated only because their contemporaries influenced them in this way, but that by no means suggest they would feel this way about woman today. Although this did not answer your question outright, I felt obligated to expunge any misrepresentation of the rabbis for people unfamiliar with the context. In the end we should judge the act and not the actor.