I don’t understand why men feel they are such experts on why girls and women do anything yet remain silent about why they behave as they do. Maybe you would care to offer some insight? Is it because men feel they have greater insight into the motivations and emotional lives of women than women do? Is it because men are reluctant to talk about their own emotional lives or why they do what they do?
I didn't say I was an expert. No one, of any gender, can fully read the mind of another person anyway and so one couldn't know in any particular case what the reason or reasons were for someone choosing to wear something or make themselves up in a certain way. I have helped raise two daughters to aldulthood though and both went through the teenage phase described in the OP, so I have some reasonably good secondary insights. For instance, both felt certain social pressures to dress the way described in the OP, though in the end both resisted them, especially the younger one, who is now, I am proud to say, a moderate feminist. The older one is no slouch in the gender issues department either, though I don't think she would self-identify as a feminist. She's generally sexually-oriented towards women anyway so dressing to impress the opposite sex was never her thing.
As to make up and certain other things being an aphrodisiac to men, this is supported by science, and is fairly obvious anyway.
For instance, why would any man wear white tube socks with sandals? Who, exactly is a man trying to attract with that look? Or with mutton chops? A beer belly? That eerie pale glow that comes from too much time in front of computer screens? Or is it that men cannot bear to consider that they are not at the center of any woman's every waking moment and every thought and motivation, however unconscious?
Imo, many men (and teenage boys) do not generally feel they need to go to such lengths as girls and women do to make themselves smart, presentable or attractive. There's probably a variety of reasons, but my guess is that one of them has to do with male privilege and the (in some ways discriminatory) expectations put on girls and women, including by advertising. That said, more of the same expectations and pressures are being put on men and boys. There is some truth in saying that traditionally (ie in more patriarchal days) it was the female of the human species that was 'supposed' to 'display' themselves in many ways, including in 'mating' situations (love, romance or sex).
Imo, having been gone through my teenage years in the 1970's, things have gone backwards in this particular respect. I am not sure why. Girls then did not seem to go to the lengths that girls nowadays do and the sexes were less 'split' into two distinct 'appearances'. It's a pity.