Given any site has a large enough userbase then eventually two people will meet and on it, even sites which are paradoxically sexual like sites / smut sites - that advise you not to meet others.
I like to think it's because you just can't control the tides of humanity no matter what moderating forces you're putting in. If two people meet who want each other, societal boundaries, especially internet ones, will evaporate.
This gets even easier when your site has meet-ups each year. Host an EM BBQ, easy hook-up place. That's what they did with Kingdom Under Loathing, site romances are also irl romances a lot of the time.