Tunnocks. There are all sorts of reasons why women want to swim away from men.
(I swim fast but still find men swim selfishly.)
Body consciousness, which does not necessarily mean fat, is one. A lot of women feel uncomfortable in a swimming costume.
However I think it is fair to say that swimming is the perfect exercise for people who are unfit and/or overweight. Less pressure on the joints. And that people are overweight are often worried about wearing a swimming costume in a public swimming pool.
(I am basing this from experience of an overweight friend from a mother and toddler group who really wanted to take her child swimming. All sorts of barriers, from buying the costume in the first place to worrying about being stared at. For many women, womens only sessions feel more forgiving.)
Its the same old, same old.
Men dont have to justify why they want to be in womens spaces. Women instead seem to need to explain exactly why they want to retain existing sex segregation. For me certainly, wobbly bits and an elderly bod are one. With the discussion then loaded against them. My reasons are my reasons. If they are not acceptable I simply dont go.
And this is what will happen. Women will vote with their feet, leaving the confident and the cross dressers to enjoy their empty lanes. (Till the leisure centre closes through lack of custom, and NHS queues grow because people at risk stop exercising.)