Originally Posted by
s_bushido
Yes, if they included women in the Rohirrim and then made it a plot point to exclude Eowyn for no other reason than that she was a woman, that would make no sense. But if they wanted to include those same changes to the army and keep her story intact, literally all they'd have to do was emphasize that she was the last family Theoden had (that wasn't either already dead or potentially riding to their death with him), and he wanted to keep her safe while setting her up as the leader and defender of Rohan if he and the rest of his soldiers should fall in battle.
This isn't hard. Nor is it a good idea to assume that simply because this culture that existed thousands of years before Eowyn's story took place are depicted a certain way, that it should effect her and her culture.