This discussion is getting very peculiar (this is the first time I've seen it) but what stands out for me is one of my pet hates - the assumption that "ladies" is the female equivalent of "men". NO!!!. Ladies and gentlemen, men and women. To call women "ladies" when you are comparing them to "men" sounds to me patronising, as if they are not real people but rather decorative little things (providing they have their make-up in place) not fit to join in proper pursuits.
As for women-only or men-only classes, it seems to me that if there is a demand for either, go for it, but if not, why should any business, including a council-run leisure centre, waste money these days?