I didn't really notice a trend of autistic girls in particular liking the Powerpuff Girls. I think it's a thing quite a few girls in general liked.
I used to love it when I was little, because I liked the cute designs of the triplets, were but I also loved how, despite the main protagonists being girls, the show wasn't 'girly' or patronising unlike some other shows with female protagonists. It had its fair share of action and clever comedy. I used to have the dolls as well. (*^^*)
Even now I think the original series (not the 2016 reboot - pure sacrilege) is one of the better shows of Cartoon Network. I like how it parodies common superhero tropes, and doesn't aim at one audience in particular - it offers something for both kids and adults to enjoy.
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I'm sailing across Spectrum Sea, in my little boat.
The waters of the port were choppy. After I set off, there was a long, massive storm.
Years later, however, the sea calmed. I'm still on tranquil sea, but I'll never reach the Neurotypical Beach.