Theoretically speaking, since Fletcher has never been seen wearing her uniform properly in source material unlike Johnston, it might have started with her as the role model. Johnston was simply trying to emulate her big sister to increase her appeal, even if she's actually more used to modest appearance.
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...Didn't you always wear it properly back in America?FUEH!?Riiight?DE FACTO STANDARD BODY!!It's because I was the first one to come to Japan as representative of Fletcher-class shipgirl!!Wroooooong!! That's not what I meant!!Phew...
I managed to fool her somehow...SobsThis is... uhh... You see!!was to appeal to everyone in Japan, otherwise it's pointless!!I figured that the best way to show off the brilliance of the most successful mass-produced Fletcher-class' bodyEven though it's a bit embarrassing to expose so much skin...StripLet's do our best together for the sake of our sisters' honor!!So that means I'll have to strip down as well!!Hey, Johnston? Why are you wearing your uniform so sloppily to the point of showing your shoulders and even your chest?The truth is, I started wearing my clothes like this to attract a pair of eyeballs, but there's no way I can say that now can I...!!So that's how it is...
You've been working dutifully to maintain our sisters' honor, in an unfamiliar country all by yourself...
You've done splendid job...