First of all, bullies come in all shapes and sizes. It's very common for males to pick on females, because females are physically weaker. You don't need to be a buff dude to do that.
Second of all, take a closer look at Gou's face. She obviously looks hurt, hence the tears. There's no smirking or evil look on her face. Some jerks took her notepad, her friends and brother came in to help, the bullies get intimidated and just hand it back to her. That's as simple as it gets, I don't quite understand where you're coming up with all these other elements you mentioned.
From my experience, females pick on males just as often, especially the unpopular ones. They also pick on isolated girls, especially if they have buff "friends". The term "Alpha Bitch" doesn't exist for nothing FYI. Sure, females are less violent... in appearance. If given a chance, female bullies are just as violent and just as vicious, if not more, than bullies with a penis.
And just because a girl looks hurt and puts on the waterworks, it doesn't mean that she isn't smirking inside. Seen it way too many times. If there had been a little comic to support your claim, I just might give some credit to your story, but then again just her brother or Makoto would have sufficed, not the whole crew to take on 2 scrawny guys, one of which she could easily overpower since he's merely an inch taller . You're just pushing a wish fulfillment here, nothing else. And a "woman = always the victim, never the instigator" mentality that I kinda dislike.