An intelligent, confident woman would pursue anti-harrassment policies and understand equal opportunity laws and/or go get a cop job in Bludhaven or anywhere else she could do what it is she wants to do for a while, seems like to me.
If she could do that, than she wouldn't be Batgirl. She'd be Detective Gordon. The story can't allow that. Therefore she can't do that.
It's also not unreasonable to expect that eighteen-year-old single civil-servant parent income Babs, whose father is a big name in law enforcement and actively opposing her efforts, wouldn't have the financial or emotional to pursue a lawsuit against both the government and her own dad, or the interest in working a job that she got into by legally forcing her way and therefore immediately placing herself in resentful opposition to her boss and coworkers.