Fashion is something which
changes.
Therefore, DD doesn't like it.
ROFL
Men and women used to both wear short shorts.
They still do.
Then long shorts come (back) into fashion. Men suddenly all start wearing them, because according to the above poster, the only reason men DIDN'T wear them previously is they weren't available. Long shorts are supposedly so much better for so many different reasons.
People above have given sensible answers you have chosen to ignore, I sense a pattern....

The bottom line is you seem to be making the assumption that people only wearing shorts to get a tan, which is far from correct.
Personally, if I'm walking round town on a sunny day I don't want to be wearing trousers, equally I don't want to be exposing almost the entirety of my thighs! Think of the children! (Actually you better not, especially if you're wearing short shorts...)
Yet they are available for women too, but many women choose to still wear the short ones. Why would they do this when apparently there are a whole range of non-fashion-related reasons why long ones are better?
Women are in general "prettier" than men, they get away with wearing "sexy" clothes that expose more of their skin. I realise you rarely wonder outside of Essex but surely you realise this?
Is it any wonder women with nice legs like to wear short shorts to show off their pins (and yes sadly the ones with thunder thighs sometimes do to)? Short shorts generally only look good on men if they have nice legs, or have a certain "metrosexual" look (see Ronaldo).
There's a time and a place though, I wear short(ish) shorts on the beach for example. Who knows maybe it's my Victorian-esque sensibilities stopping me from wearing them round town?
I must admit I thought there'd be a few more people prepared to think outside the box when I started this thread, than just reply with the knee jerk 'omg short shorts are gay lol pedo' type rubbish

(I wonder whether knee jerking is easier in short or long shorts btw

)
That's quite rich coming from you. What exactly does fashion mean to you? I'm not one for sheepishly following the latest trends, but I will certainly investigate them and make my own judgement if I like it or not.