All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
We have clarified in the Fatwa that you referred to in the question the meaning of public bathrooms, and that these bathrooms might be used for washing or healing and the like. Some of these bathrooms that are founded nowadays are like those used in the past, but many people expose their ‘Awrah (parts of the body that must be covered in Islam).
What you have described as modern public bathrooms might be more harmful than the traditional bathrooms, because of the disappearance of religion, decreased piety and weak faith, it is feared that these bathrooms contain cameras which are unseen for whoever enters them, and which could see the naked bodies.
The ruling about women using these bathrooms is clear in the Fatwa that we referred you to.
The meaning is the same about women visiting health service clubs (balneotherapy), steam spas (sauna), and private swimming pools for women are the same type as public baths. What is intended here is that females should exaggerate in covering themselves up to protect their honor and dignity. Hence, the woman staying in her home was better for her and her community as she should not go out except for a need, as Allah Says (what means): {…and abide in your houses.} [Quran33:33]
Ibn Katheer said in his Tafseer: “His saying: {And stay in your houses} means, stay in your houses, and do not come out except for a purpose.” [End of quote]
By them staying in their houses, they would protect their honor and dignity and close the doors of temptation.
Allah knows best.