You can hear every once in a while that girlfags are not "allowed" to use the word fag. Because "fag" is a slur and only gay men are (should?) be allowed to reclaim/reappropriate it.
Def. Reappropriation is the cultural process by which a group reclaims—re-appropriates—terms or artifacts that were previously used in a way
disparaging of that group.For example, since the early 1970s, much terminology referring to homosexuality—such as gay and (to a lesser extent) queer and poof—has been reappropriated.
Of course it's true that "fag" IS slur - especially for effeminate or flamboyant gay men. But this includes somehow that effeminate or flamboyant men can't be proud about this. But they can. They reclaimed the word and can proudly call themselves fag. But are girlfags allowed to do so, too?
The term "girlfag" was coined in the 1980s. It's not popular among all gfgd - out of the obvious reasons. But it's established now and it gave a group of people, who had no name so far, the possibility to talk about themselves.
To quote Janet Hardy:
"About the word - which we all agree is a problem: only nobody has come up with a better one yet in English. It's not a problem in languages where there is a single non-vulgar word for 'gay man' - but 'gay woman' simply means a lesbian, as opposed to 'male lesbian', which works fine and is coming to more common use. But nobody's come up with a decent substitute for 'girlfag' in English."
That's very true, as in german there is a non-vulgar word for gay men - "schwul". And nobody ever complained about someone identifying as "schwule Frau" (Frau = Woman). So if you have another, good idea for an english term - please let us know.
Also: Girlfags identify with the LGBTQ-culture. You can't deny them their queerness. So they are part of that marginalised group - and under a certain light this gives them also the right to use the slang.
Oh and by the way: I never heard anyone complain over the use of "fag hag". Seems like the term "fag hag" is completely acceptable - although it contains "fag".
Have a look here, too.