The introduction is a catalog of ambiguities about sex, gender, and sexual orientation:

My partner was diagnosed male at birth because he was born with, and indeed still has, a fully functioning penis ... My partner's DNA has a pattern that is simultaneously male, female and neither. This particular genetic pattern, XXY, is the signature of Kleinfelter syndrome ...

We've known full well since Kinsey that a large minority...37 percent...of men have hat at least one same-sex sexual experience in their lives.

No act of Congress of Parliament exists anywhere that defines exactly what heterosexuality is or regulates exactly how it is to be enacted.

Historians have tracked major shifts in other aspects of what was considered common or "normal" in sex and relationships: was marriage ideally an emotional relationship, or an economic and pragmatic one? Was romantic love desirable, and did it even really exist? Should young people choose their own spouses, or should marriage partners be selected by family and friends?

As unnumbered sailors, prisoners, and boarding-school boys have demonstrated, whether one behaves heterosexually or homosexually sometimes seems like little more than a matter of circumstance.

Masculinity does not look, sound, dress, or act the same for a rapper as for an Orthodox Jewish rabbinical student; a California surfer chick does femininity very differently from a New York City lady-who-lunches.

All of these are fair enough, and I've only read the introduction, but I don't have a lot of confidence that she goes on to resolve these contradictions in Less Wrong tree-falls-in-a-forest style. Instead of trying to clarify what people mean when they something like "most people are heterosexual," I get the feeling she only wants to muddy the waters enough to say "no they aren't."

Oh, so her thesis is that in the west, orientation-as-identity dates back to 1860-ish. I can imagine that being defensible. That's way different from what you originally wrote, though.

You see, the first thing that came to mind was Aristophanes' speech in the Symposium, which explicitly recognizes orientation-as-identity and predates the Catholic Church by a couple centuries.

It made me a lot more comfortable dealing with people who might be seen as "regressive", "bland", "conservative" or just who seem otherwise not very in-synch with my own social attitudes and values. Getting to understand that culture and culturally-transmitted worldviews do constitute umbrella groups, but that people vary within them to similar degrees across such umbrellas, made it easier to just deal with people and adapt my own social responses to the situation, and where I feel like the person has incorrect, problematic or misguided ideas, it made it easier to choose my responses and present them effectively.

It made me more socially-conscious and a bit more socially-successful. I have some considerable obstacles there, but just having cultural details available was huge in informing my understanding of certain interactions. When I taught ESL, many of my students were Somali and Muslim. I'm also trans, and gender is a very big thing in many Islam-influenced societies (particularly ones where men and women for the most part don't socialize). I learned a bit about fashion sense and making smart choices just by noticing how the men reacted to what I wore, particularly on hot days. I learned a lot about gender-marked social behavior and signifiers from my interactions with the older women in the class and the degree to which they accepted me (which I could gauge readily by their willingness to engage in casual touch, say to get my attention or when thanking me, or the occasional hug from some of my students).

It made me a far better worldbuilder than I was before, because I have some sense of just how variable human cultures really are, and how easy it is to construct a superficially-plausible theory of human cultures, history or behavior while missing out on the incredible variance that actually exists.

It made me far less interested in evolutionary psychology as an explanation for surface-level behaviors, let alone broad social patterns of behavior, because all too often cited examples turn out to be culturally-contingent. I think the average person in Western society has a very confused idea of just how different other cultures can be.

It made me skeptical of CEV as a thing that will return an output. I'm not sure human volition can be meaningfully extrapolated, and even if it can, I'm far from persuaded that the bits of it that cohere add up to anything you'd base FAI on.

It convinced me that the sort of attitudes I see expressed on LW towards "tradition" and traditional culture (especially where that experiences conflict with global capitalism) are so hopelessly confused about the thing they're trying to address that they essentially don't have anything meaningful to say about it, or at best only cover a small subset of the cases that they're applied to. It didn't make me a purist or instill some sort of half-baked Prime Directive or anything; cultures change and they'll do that no matter what.

It helped me grasp my own cultural background and influences better. It gave me some insight into the ways in which that can lock in your perceptions and decisions, and how hard that is to change that, and how easy it is to confuse that with something "innate" (and how easy it is to confuse "innate" with "genetic"). It helped me grasp how I could substitute or reprogram bits of that, and with a bit of time and practice it helped me understand the limitations on that.

There's...probably a whole ton more, but I'm running out of focus right now.

EDIT: Oh! It made me hugely more competent at navigating, interpreting and understanding art, especially from other cultures. Literary modes, aesthetics, music and styles; also narrative and its uses.

Me too.