The other point to make is that OkCupid's protest cost them nothing. If they really cared, their registration page could have the usual checkbox: I hereby agree to blah blah terms and conditions, and a second checkbox saying: "I affirm my support for gay marriage rights." Failing to select both boxes would bounce the user off of the OkCupid side.
But no, they wouldn't do that, because that might cost OkCupid business.
It's worse than that. Central to OkCupid's algorithm are the match questions, several of which are explicitly about homosexuality.
Not only does OkCupid make money from the homophobic, they are precisely aware of exactly how much of their income is derived from the homophobic market.
Perhaps they could write one of their famous data-driven blog posts, showing the world exactly how much money they make from anti-gays, creationists, climate-change deniers and the like.
But no, they wouldn't do that, because that might cost OkCupid business.