That's not the effect it has. An anecdote is never anything but harmful. It's an unsubstantiated, unproven, individual experience that often* goes against the actual data and proof in the discussion. All it does is let idiots blindly latch onto it, screaming "See? This is proof that women deserve to be paid less!! I never have to open my mind!!"
I don't know how you don't get this. How badly do you want it to be okay for you to film little girls in public? Just because something is legal, doesn't mean you should do it. Kindergarteners are taught this. How do you not get it?
Just because it isn't illegal, doesn't mean it's okay for you to do. Filming people in public without their permission is considered rude and, if its old man > young girl, creepy.
There's a difference between security cameras filming a large area where large numbers of people cross, to ONE person with ONE camera filming HER specifically. You should know you have no legal expectation of privacy, but it's still rude and creepy to film people in public without their permission.
Filming a teenage girl in public is okay? How about you sit in your car with a video camera filming schoolchildren and tell me how that goes. It's creepy, you shouldn't do it.
Legally, no. But it's common courtesy not to film people without their consent. If you do, you're being a dick and (if you're filming a young girl) a creep.