Want to meet people with herpes? Mental Floss finds a bevy of niche dating services. My favorite (hypothetically, of course) is WeNeither, where people match up based on shared aversions. FWIW, 18 entrants say they avoid Republicans, one avoids Democrats. (Most commonly detested is smoking.) I had to suspect nondaters gaming the site when I found six entrants who avoid people, two who avoid the internet -- and none who admit that they don't care for long walks or sunsets. What aversion would you display?
(Inside joke: I haven't seen one yet for left-handed chess players.)