Yeah, I get it, I really do - and I support it. Sexualising girls is vile. Of course it is. Not going to argue with that.
But one bit of it - that I didn't get till I was well into my thirties - is the nostalgia factor. It was explained to me thus:
Boys, at some point in their teens, are suddenly hit with a blast of sexuality that they can ill-control. The sight of the pattern on the damned carpet is enough to give them stiffies.
I think it's a shock to their systems, the poor dears. And, they remember that feeling forever. The first ever time their knobs woke up and absolutely refused to go to sleep for the following five or so, uncomfortable and frequently awkward, years. Girls suddenly stopped being the squealy small irritating things, and became magical beings ....
If I'm right, it wouldn't make the blindest bit of difference what schoolgirls wore in the past, or wear now. It'll press a button for men in their twenties, thirties or forties, regardless - and that, for better or worse, is one major reason why it's such a grindingly embarrassing perennial kink.