I think they just have a bias toward the shoujo heroine/supporting love interest types, who don't really compete or come into confrontation with boys but instead are focused on their own separate goals in the own feminine sphere so to speak, which often involves romance. As such, they are more cooperative than competitive (when it comes to guys, at least). I can definitely see the reason behind calling May a tomboy. Hell, I thought she and Dawn were the more balanced heroines and are actually equal to the male protagonist. Misty and Serena attract awful shippers because they can really ONLY see the girls as love interests for their self-insert.
>>37610902It's funny because Misty acts like a little bitch all the time. The thing about a lot of tsunderefags and some tomboyfags is that they aren't actually going for strong-willed or rough & tumble types. They like the moe factor of a bitchy, needy, overly sensitive and sensationalist girl who's just as, if not more, stereotypical than the "girly" types, as much as any greasy Japanese otaku, only the Japanese otaku are self-aware about it. Shit, Persona 4 does the joke where the tomboy freaks out over bugs and ghost stories, while the yamato nadeshiko and even the loli don't. Basically those characters are very "girly" where it matters.