...and please don't refer to this as the gay dolphin conspiracy..
I'll refer to it as another bigoted and ill-conceived argument, and an offensive one at that. In it you clearly claim that heterosexuals are superior to homosexuals in some ways. And if we're to follow your metaphor literally, then homosexuals are a different species all together. Gays are uniquely different than straights - but they are still human beings deserving of the same rights under the law.
How is it not bigoted to claim that one group of people is inferior to you based solely on an innate part of their identity? How is it not offensive to make a comparison between fish and dolphins (two entirely different species) and heterosexuals and homosexuals?
I would tread very carefully on this line of argument if I were you, diamond.