I don't really get why they need to belittle the idea that it's nice for little girls to grow up with a super hero that they could look up to.

Because they're right, it is bullshit. Why are we pretending that little girls have never had role models to look up, fictional and not? I've heard this phrase thrown around whenever a new female-led movie comes out in recent years, including garbage like Jem and the Holograms, and Ghostbusters (2016).

I was a little girl who grew up on media from the 80s and 90s, and while there weren't very many heroines in movies (there was always Sarah Connor and Ellen Ripley at least), I admired She-Ra, Scarlett, Lady Jaye, Jem, Penny (Inspector Gadget), Gadget Hackwrench, Sally Acorn, Trini Kwan, Storm, Rogue, Belle, Jasmine, Batgirl/Barbara Gordon, Sailor Moon, etc. I never felt great female characters were in short supply. Not to mention that even as a female, I still admired many male characters as well.

I'm glad there's more selection popping up in the world of fiction for girls to delve into, but let's not pretend Wonder Woman or whichever flavor-of-the-month movie characters are all girls have to turn to for enjoyment.