WAvegetarian and incalescent are right.
Many of the older dorms just have one bathroom per floor with one set of showers and stalls which are almost always just open to everyone or are on E-system as Ma’ayan described back in 2011. All of these bathrooms have individual stalls with doors or curtains, except maybe Harkness, but you have to apply to live there so it’s not like you’re just going to be placed there.
Making the bathrooms gender/sex neutral (I can’t even tell which one people are wanting to segregate the bathrooms by, not that either makes any sense) helps make them safer for everyone who doesn’t conform to the gender binary. Obviously there are traumatic events that could make students uncomfortable using bathrooms with people of a different gender, but for the most part I think most students would think having gender neutral bathrooms just helps the campus be a more welcoming and safe place.