I think the uniform dating site was about uniformed workers getting a bit of action with people who had a uniform fetish nothing to do with needing to be in uniform for both parties.
I remember years ago reading in a at the time quality newspaper about a certain uniform fetish from Japan. Apparently the Japanese national airline was very strict about their uniforms. If you left they sent security to collect it. They sold for £30,000 in the 90s and that's for good replicas!
I can't see what people get out of them personally but each to their own.