Why is the "gifted sister" discouraged from reading and writing?

I would say she writes this piece for women with the earnest hope that men might read this and understand what she is trying to say. Woolf posits that men historically belittle women as a means of asserting their own superiority. In her metaphor of a looking-glass relationship, men, threatened by the thought of losing their power, reduce women to enlarge themselves. However, just as women's writing suffers from the emotions of anger and fear, men's writing suffers from this aggression. The men the narrator reviews do not write "dispassionate," detached arguments that would otherwise convince the reader, but expose their own prejudices. In the end, their writing revolves around them rather than around their subject. Woolf points out that war is a greater societal byproduct of this consuming aggression and defensiveness. Woolf imagines what would have happened had Shakespeare had an equally gifted sister named Judith. She outlines the possible course of Shakespeare's life: grammar school, marriage, work at a theater in London, acting, meeting theater people, and so on. His sister, however, was not able to attend school, and her family discouraged her from studying on her own. She was married against her will as a teenager and ran away to London. The men at a theater denied her the chance to work and learn the craft. Impregnated by a theatrical man, she committed suicide.