It is entirely reasonable to assume that there is a biological basis for the sex differences in men and womens fashion. There may not be proof that the sex differences are innate, but it's reasonable to propose that they are innate.
By the same token, it is unreasonable to deny that these sex differences are innate, until such time as proof is offered.
> I have to say I'm quite suspicious of inherent genetic traits that only reveal themselves when the textile industry appears
There's also every reason to believe that people were modifying their appearance before textiles were around. See scarification, use of colored clays / paints, etc. Even something like singing can be used as a way to attract mates. There's no reason to pick textiles as the sole use of fashion.
Regarding the example, I was picking on one given, particularly on the seasonable part. I realize people were adorning themselves before the industrial revolution. But then again, people of all genders were doing that.
I mean, I don't trust the processed food industry either, and will readily admit that they do everything they can to manipulate human desires for profit. Do people have an innate desire for Coke and chicken nuggets? No. But looking at what the industry does, and then using that to conclude that (most) humans have no instinctual tendency towards sugar and high fat foods seems mistaken.
That the fashionable seasonable colors is associated with the feminine gender is true, but it says nothing about whether it's an inherent trait, as you imply, or something created by society.
I have to say I'm quite suspicious of inherent genetic traits that only reveal themselves when the textile industry appears and has to find ways to get people to buy more product.