I wonder if they think it would be ok for the women to be in the men’s bathrooms at the same museum? Sure there are separatel women’s bathrooms, but do the women’s bathrooms have urinals for them to use if they wanted to?

I don’t think there should be a women only space in a general museum, except to make a point, but the cost of admission is not the argument to win that fight. If it’s to make a point, it shouldn’t be enforced.