This is silly, and not just because you call yourself a rationalist (drop and give me Bayes Theorem! ). You seem to have no concept of what we’re even talking about; it’s like having a discussion about privilege and someone barges in and says, “I had the immense privilege to jam with half the members of Phish” - okay, damn cool factoid, but that’s not even tangentially related to what we’re actually talking about.
When we talk about the “default” when talking about identities, we are necessarily talking about it in the context of a specific niche. The default identity when it comes to any given category one would talk about in identity politics. To run down the basics:
[li]The default skin color is white[/li][li]The default gender identity is cisgendered[/li][li]The default sexuality is heterosexual[/li][li]The default ability level is “not handicapped”[/li][/ul]
…And so on, and so forth. The “default” here refers to how, in society, when people consider the “everyman”, they’re thinking of, well, you. The everyman is not my friend Jacquii, a queer trans black woman. It’s not my friend Shu Ning, a nonbinary asian person. It is, however, pretty close to you. If I were to swallow my occasional desire to suck a dude off, I’d basically be the everyman, the default template of modern western society.
(Basically, think “Nathan Drake” and you’re 99% of the way there. And if you were ever wondering why so many characters in film, comics, video games, TV, etc. are cishet white men, now you know.)
But here’s the thing - if you’re the “default”, society doesn’t take your existence as a threat or a challenge. You’re just… the way things are. What’s “weird” or “strange” is people deviating from that norm. Those are the people society tends to marginalize, socially or legally. And those are the people for whom identity politics is really important. Because, at the end of the day, they are being persecuted because of part of their identity. And when they band together under the banner of their identity, they can end that persecution much more effectively than they can as isolated individuals.
Let’s make it really, really, really fucking simple.
Imagine that you are a gay man in Texas before Obergfell. Do you feel that your identity as a gay man should have any relevance on your politics? How about as a gay man in Texas before Lawrence? How 'bout as a black man in Georgia before the Civil Rights Act. Imagine one party is saying, “Segregation now, segregation tomorrow, segregation forever” and the other is saying, “Equal rights now” - do you think that would impact your vote at all? Do you think that, as you put it in another thread, it’s the “least interesting thing” about you when it comes to how you’ll vote? I’ve never been in that position, but I can’t imagine it would be anything short of the single most important issue I could possibly vote on - assuming I could, in fact, vote.
That is why identity politics matters. You may personally think that your sexuality is the least interesting thing about you. But what if the laws of the country you live in considered them so important that they carved out laws explicitly to persecute you? Would it feel more important then? I promise you - the societal “default” never has to deal with that shit. They never have to think about what life would be like if they were persecuted. They never have to even check their privilege, as much as we all wish they would.
This is the essence of identity politics. If it doesn’t matter for you, consider yourself incredibly lucky. Because that means that you, like me, basically got a royal flush of privileges. You’re white (don’t have to worry about systemic racism), male (don’t have to worry about systemic misogyny or people forcing you to carry your rapist’s child to term), cisgendered (don’t have to worry about the government literally defining you out of existence), and heterosexual (don’t have to worry about gay-bashing or people revoking your rights). But for people who don’t, as John Scalzi put it, “Start life on the lowest difficulty setting”, these issues are:
B) Deeply political
That’s why identity politics exists.