Like every other expression of human culture, homosexual and heterosexual identities are historically transient. They haven't always existed, and they won't last forever. Indeed, the weakening, blurring and eventual dissolution of the labels queer and straight will be final proof of the demise of homophobia.

Um. It's a take on this that may be more about semantics than anything else, but from the social constructionist and post-modernity points of view, what Tatchell claims here could make sense.