I'm not sure I'd have defined slash as the big unifying thing of fangirls. I think it's rather fanfics in general. Lots of women prefer het or gen to slash. But fanfics in general seems to be majorly female dominated.

However I'm not surprised some women like you still feel excluded from the "female space" thing of fandom because they don't totally identify with those activities :/

I'm glad lots of people would like a non gendered fandom ^^