I'm very sceptical of these evolutionary psychological explanations for what we are attracted to.
And it doesn't matter.
While it's not of direct practical use why do you question the idea?
Any species, selecting mates for reproductive fitness is going to be selected for.
I'll explain.
The human penis shape, and how men feel pleasure, is designed for pumping/pulling out cum from the guy in front. Chimpanzees mostly have gang bang/group sex type sex. Gorillas don't. They do one on one style sex. So a gorilla penis is optimised for that. Our closest relatives are bonobos. Often have group sex. So that can explain it. Human penises are more like chimpanzee penises. Does this mean that humans primarily have gang bangs, or so often that evolutionary pressure will shape the penis? No. Because if humans at some point started sliding towards a more monogamous sexual lifestyle, which is the norm now, it won't put much evolutionary pressure on the penis design, to change it. So it's genetic drift.
So what exactly can we deduce about modern human sexuality based on the size and shape of the human penis? Exactly nothing.
Something I've heard plenty are people claiming that the reason women are picky about which partners they have is because women need to carry the baby around for months and then need to take care of it. As it turns out, by studying modern hunter-gatherers we know that's nonsense. Hunter gatherers take care of children comunally. Which specific man births the child is largely irrelevant. They're all in it together. Sex is often ritualised and controlled by the tribe. When I was in Colombia I was in a Wiwa tribe village. They're semi nomadic. Once per year they hang out in a special sexy village. The village elders pair them up and the lovers get to live in sexy huts alone for a while. Then they leave the village. This is common. because hunter gathers want to time child births so that they're staying put in a good place when it's time to birth the kids. Nine months down the road. That's another settlement the Wiwa people go to. Basically, sexuality is often controlled by village elders and out of the lovers control. That's most likely the kind of sexuality and sexual instincts we've evolved for.
People claiming that women are picky because women need a strong man to protect them is modern conservative clap trap projected onto the ancients. It doesn't at all reflect how hunter gatheres have sex or pair bond. It seems like what we've evolved for is having arranged marriages and having sex ritualitically in an arranged fashion.
Not to mention that hunter gatherers were unlikely to understand that sex led to babies. The time it takes between the sex and the first sign of pregnancy takes so long that it's unlikely pre-moderns ever figured it out. Which might help explain all the bizarre birthing myths associated with gods.
We also don't know if the size and impractibility of peacock feathers signal fitness and therefore is what gets them laid. They do all kinds of stuff when courting peahens. It's just a theory.
When it comes to sex and sexuality we have a terrible habit of projecting our own personal politics onto biology and we seem to love biological determinism.
I hang out in the Danish queer community, and the amount of absolute idiocy my tribe often believe, and have really strong opinions on, is astounding. It's a bubble of progressive values and opinions, and the people who only stay in the bubble keep getting their beliefs reenforced. I'm going to assume that this is true for everyone and every comunity. People seem to love having strong opinions on it. And I think that available evolutionary evidence can be used to prove basically anything about our needs, urges and instincts.
For that reason I've chosen to have a humble stance on it and admit that I don't know, and stay skeptical when people are confident about it.
Its more important to establish which traits are attractive rather than to explain why they're attractive..
Why are femme lesbians so often attracted to butch lesbians? Good luck finding a logical explanation for that
Actually, I see an entirely logical explanation.
I am in the camp that thinks there isn't really a genetic "heterosexual" or "homosexual". Rather, we get a far simpler model if we look at intensity and filters for the desired criteria, two independent controls rather than a messily-linked "same-sex" and "opposite-sex" attraction.
Thus an asexual has the intensity at near zero, the filters don't matter.
A heterosexual man has the filter of "woman", a bisexual man has both the "man" and "woman" filters.
While such things (gender, sexual attraction) are supposed to be paired biology always messes up pairing, the only question is to what degree. And note that the filters aren't really to "man" or "woman", but attributes. Your butch lesbian has more male traits. This is a "male"-female pair where certain female attributes replace the base male attributes.
And it explains why genetics does such a poor job of selecting against it--we need the pattern to survive.
I believe that making a species that continually gets their retinas hammered with media triggering dopamine hits and not given much time to sit and reflect, will get a perverted sexuality.
I think we live so far from the lives we've evolved for, that it's damn near impossible to take modern sexuality as any kind of indication for what's natural or normal for our species. Gay, bisexual or otherwise.
I'm on Matt Ridley's team when it comes to homosexuality. It's a mystery. It's not functional. There's no possible scenario we can model that makes homosexuality adaptive or increase fitness. No matter how we mess around with the data, the bottom line, is that fitness and survivability would go up if everyone could potentially have babies from reproduction. It also exists in all mammals at about the same proportions. So it's impossible to breed out (which we've tried to do). One theory is that the genes for homosexuality sits on the same gene or chromosome as something that does something really really important, so therefor has a too high cost for the species to breed out. So it stays. Genetic drift. But ultimately... we don't know. And does it matter? Love is love. I really don't need to know why other people fancy eachother. If it makes your dick hard and you get consent.... fuck it.