regarding "White Feminism"
Feminists and SJWs have a well-established history of ignoring facts and instead deciding who is correct in a situation based on oppression points. So while it is okay for a cis white straight feminist woman to bitch at cis straight white male scum, it is less okay for cis white straight feminist women to bitch at other cis white straight feminist women.
Considering that cis white straight women are by far the majority population in feminism (and especially in e - feminism), most of their hissfits at each other end in a stalemate. A good way to break that stalemate would be to claim or pretend that your opinion covers other groups with more oppression points as well. An easy way to do that is to bring in race which is how we end up with whiter than chalk feminists complaining about white feminism at other people (including, in some hilarious cases, minorities).
A really funny example was when Lena Dunham was outed by her own book as perving on her 8 year-old sister. Many feminists supported Dunham while some condemned her. The "condemning" side of the argument decided that Dunham received support because she was white and used that as a weapon, like in the following article
http://feminspire.com/white-feminists-fucking-ignoring-lena-dunhams-abuse/2/
In that article there is nothing to support the "white" part of the "white feminists". It's just put there to claim higher moral ground (oppression points) and silence the opposition in this inter-feminist catfight in the same way feminists try to devalue men's opinions (unless they are men who agree with them) by pointing out that they are men and supposedly have less oppression points.
Do I doubt that most of Lena Dunham's feminist supporters were white? No, of course not, that's because the vast majority of (e-) feminists are from the U.S. and Europe and they tend to be privileged in aspects that actually matter (e.g. wealth and social class) so they are more likely to be white. But I haven't seen a single reason to label them as "white feminists" other than the usual feminist oppression game.
In Brianna's case, she hasn't activated the Tranny card yet so she is considered just a white straight cis feminist which is a dime a dozen in feminist circles and doesn't give many oppression points. So she has to look elsewhere.