Besides, real-life conversations don't reflect the biases of an external writer. Whatever women discuss in real life will reflect their own thoughts and concerns. What gets discussed by female characters written by male authors in a male-dominated industry is a different matter. The Bechdel Test isn't about judging every individual conversation -- it's about what it shows in the aggregate about the inclusion and portrayal of women in fiction.
No, this isn't quite right, because the Bechdel test was created by a lesbian cartoonist almost as a tongue in cheek thing. I can understand why lesbians would not find movies in which the relationships involve heterosexuals to be very interesting and might even be offended by them.
Obviously if I was watching a movie directed at a lesbian audience, and dealing with lesbian relationships, yet it never had two women talking about something other than a man, that would be very offensive. I understand that.
However most mainstream pop culture films and TV are not directed at a lesbian audience. They are directed at heterosexuals.
Which is why Bella was in love with a male vampire and a male werewolf.
Heterosexual women drive the market for mainstream heterosexual romance centered films (i.e. "chick flicks.") You can't hardly have a "chick flick" that doesn't involve women talking about men.
"Action film" market is driven by young heterosexual males and adolescents. Again, they aren't very interested in seeing two women talk about anything unless it is sexually-oriented.
So we return to the underlying question which is what dramatic situations are we really talking about that involve two heterosexual women having a conversation about something that doesn't reference a man, yet would be interesting enough to a typical mainstream audience (i.e. either action flick or chick flick) to make a movie or TV show out of?
I guess you could have a political thriller where the President of the U.S. is a female and the V.P. is also a female and they battle it out with each other.
The problem with a film like that is if there was no relationship drama component you wouldn't get very many real live women to actually bother to go see it. So if there's not going to be a relationship drama as part of it you might as well make the lead characters men, because most heterosexual men aren't going to want to go watch a movie about two female political leaders fighting with each other for political power.