Having picked up dating apps and Okcupid recently after ending a 4 year relationship, my guess is that Okcupid has become particularly friendly to people seeking BDSM and non-monogamous relationships. I had used it before and at least anecdotally what I see OKC users looking for is different from before. A lot of people have moved to swipe dating apps like Tinder and Bumble where the focus is almost entirely on photographs and not what users write about themselves. Maybe Okcupid is drawing users into BDSM and other non-traditional relationships because they can talk about it in their profiles and potential dates may actually pay attention rather than just swiping.
Clicking on yes i like to be tied up in a 100 questions survey is veeery far from actually liking it IRL
You would have to be to get through all their surveys!
Better hurry up and fire all of them from their work and open source projects! /s