>>57987521My guess: Cute/attractive designs + in-universe competence (they are basically prodigies) + not too much of a personality (so you can project your desired traits onto them). But for that last point the inverse is also true, paradoxically for girls like Dawn/May. In the case of Dawn/May it could be that a long time spent with the character (the anime) makes people connect strongly with them as long as the character isn't fundamentally a terrible person
But the above applies to a lot of fiction. Pokemon is so popular so proportionally, there will be a large number of PokeGirl fans
But somehow I guess you are just looking for le meme hebephilia answer
