So true! The blank slate comment is very buddhist-sounding: what you are at the core of your mind before the defilements of illusions, ignorance and culture. When you're in a higher state of consciousness, you're attuned to the true nature of human sexuality. That's to say that labels are just social constructs. Do they really exist outside of culture?
Are you only what your culture defines you as?
Are we more than our thoughts? Do we let our thoughts define us?
So, what is pure and authentic sexuality? How can we see our authentic and pure sexual selves void of cultural realities? Can you really enjoy your sexuality if you operate only in a realm of what you think sexuality should be according some set of cultural norms?
I dislike it when people use "only social constructs" as such a dismissive argument. My point is that human nature itself is maleable because we are reflections of our ultimate social construct, which we call society. Not to say that social constructs are bad or good, but necessary. Social construct = neutral term. Culture and social structure is the essence of what it means to be human, and the many various constructs that class society creates (like sexuality and gender) are a part of it.
But if human beings are defined by culture and social structure, then the core of human nature is to be able to create something out of nothing. To be adaptable on a psychological and sociological level. Meaning any one person's sense of self as an individual and as member of a group is initially defined by social constructs, yet not need be constrained by them. As being a member of any one group is a choice, so too are the social constructs we may or may not abide by.
It doesn't matter whether any one person is gay, straight or something else entirely. It's about as relevant as whether a guy prefers to piss at a urinal or while sitting on a toilet. What matters is how well the social structures we create/live in function. And as such, the question of whether or not "gay" or "straight" is a part of reality or only a part of "our" reality is quite immaterial. Sexuality boils down to the experiences you accrue over time, and the choices you've made in those experiences. The intimate relations you've built and learned from. The strength of your most loving relationships. And whether these labels are a crucial part of any of that is optional, and could be anyone's guess.