Your "obvious" explanation of sexual selection does not explain why (some) women spend inordinate amounts of time and money seeking out accessories that men don't notice or care about, and continue to seek these out well after they have married and (sometimes) over the objections of their spouses. Also, I was talking about accessories, not clothing.
My explanation does not discriminate between men and women; society does. Each has a different method of showing off status. Men show off status via different accessories, namely gizmos like phones and watches and conspicuous consumption and in some cases shoes and jewelery (and cars, but those signal between genders, as well). And just because men may have more to gain by signaling status, that does not predict that they will gain status through the same mechanisms. Men who spend a lot more on clothes than their actual status justifies tend to be looked down upon by other men - status is one of those things that if you try too hard to show you have it, you lose it. The same standard (to my knowledge) does not generally apply to women.
Or, more simply, most men don't really see much about how they dress (or their appearance generally) as relating to their social status, where more women see it as being more important. This would be an evolutionary motivator (show high status) operating through a social outlet (by dressing a certain way).
I was explicitly not talking about clothing, but about accessories, so the "same outfit" really is a straw man. Though I am uncertain how sexual selection explains it better than status signaling (if someone is wearing the same thing as you that seems like it would obviously dilute your status signal heavily), but that's not the point since I was talking about accessories specifically.
My "people value looking good" also explains both of these phenomena FWIW; men don't see nice clothing as necessary to looking good, and women might have their self-image of looking good (and special) harmed if they show up dressed exactly like another woman.
I don't like your explanations because they don't really explain anything, just shuffle complexity around. "See, there's this thing called phlogiston, err status, that says you have to do this if you're a man but something different if you're a woman, for reasons unspecified."
Take a woman to a store and you'll see that the process of buying a handbag is guided by reasoning very similar to the process of buying a dress. The dress is clearly for attracting mates; what if the handbag is just a side effect, some clever marketer's way to hack the mate attraction instinct?
Disclaimer: If you are prone to dismissing women's complaints of gender-related problems as the women being whiny, emotionally unstable girls who see sexism where there is none, this post is unlikely to interest you.
For your convenience, links to followup posts: Roko says; orthonormal says; Eliezer says; Yvain says; Wei_Dai says
As far as I can tell, I am the most active female poster on Less Wrong. (AnnaSalamon has higher karma than I, but she hasn't commented on anything for two months now.) There are not many of us. This is usually immaterial. Heck, sometimes people don't even notice in spite of my girly username, my self-introduction, and the fact that I'm now apparently the feminism police of Less Wrong.
My life is not about being a girl. In fact, I'm less preoccupied with feminism and women's special interest issues than most of the women I know, and some of the men. It's not my pet topic. I do not focus on feminist philosophy in school. I took an "Early Modern Women Philosophers" course because I needed the history credit, had room for a suitable class in a semester when one was offered, and heard the teacher was nice, and I was pretty bored. I wound up doing my midterm paper on Malebranche in that class because we'd covered him to give context to Mary Astell, and he was more interesting than she was. I didn't vote for Hilary Clinton in the primary. Given the choice, I have lots of things I'd rather be doing than ferreting out hidden or less-than-hidden sexism on one of my favorite websites.
Unfortunately, nobody else seems to want to do it either, and I'm not content to leave it undone. I suppose I could abandon the site and leave it even more masculine so the guys could all talk in their own language, unimpeded by stupid chicks being stupidly offended by completely unproblematic things like objectification and just plain jerkitude. I would almost certainly have vacated the site already if feminism were my pet issue, or if I were more easily offended. (In general, I'm very hard to offend. The fact that people here have succeeded in doing so anyway without even, apparently, going out of their way to do it should be a great big red flag that something's up.) If you're wondering why half of the potential audience of the site seems to be conspicuously not here, this may have something to do with it.
So can I get some help? Some lovely people have thrown in their support, but usually after I or, more rarely, someone else sounds the alarm, and usually without much persistence or apparent investment. There is still conspicuous karmic support for some comments that perpetuate the problems, which does nothing to disincentivize being piggish around here - some people seem to earnestly care about the problem, but this isn't enforced by the community at large, it's just a preexisting disposition (near as I can tell).
I would like help reducing the incidence of:
We could use more of the following:
Thank you for your attention and, hopefully, your assistance.