Charlie Hall: “And that is pretty irrelevant to torah study because women are obligated in all but about a dozen mitzvot from the torah. It is not an “optional mitzvah” for women to learn torah.”
Torah learning is one of the dozen mitzvos which a woman is not obligated in, as the Gemara learns from the posuk “Vishinantum L’banecha V’loa L’binosecha”. Of course women need to learn the practical halachos which are applicable to them in order for them to practice them properly; however, actual studying in depth is not an obligation for them.