Understand the predicament the swimmer was in but need to take into account that in public areas like a swimming pool where there could be children, they may hit safe guarding concerns.
they’re wearing male clothes to and from the centre but decide that today they’re going to wear a female one piece swimsuit when in the pool because they want to feel more comfortable than going bare chested.
If been bare chested was the problem than a rash vest or T-shirt (if allowed) would have been better here. Same issue if a trans man decided to wear just a pair of speedos & go bare chested, exposing their breasts.
And yes Speedo's might look revealing but they are designed to keep everything out is sight, which a female costume will not.
It is not unreasonable to expect everyone's bits and pieces are kept under wraps when children are present in a public facility. A man wearing a woman's swimming costume in front of children is a safe guarding issue.