In thinking of slash (especially f/f) in the larger context, I normally think of contrasting Blakes 7 with my other fandom -- Xena.
As with Blakes 7, the show started with purely subtextual elements, but once the way in which many fans were interpreting it became known, it became deliberate policy to insert them into every episode. Thus each episode contains deliberately tantalising clues that always fall short of an outright declaration (much to the dismay of many fans). We call this "the subtext" and divide fanfic into "gen" and "alt" depending on whether the author considers the relationship between the central characters to be sororal or saphic.
As with Blakes 7, anything other than gen is extra-canonical but I would deny in both cases that it is uncanonical just because some labourious hetrosexual explanation can conceivably be constructed.
Whereas the majority of B7fic is gen and the majority of slash is m/m, Xena fic is almost evenly divided between the two, and the overwhelming majority of slash is of course f/f. That the show has such a large lesbian fan base belies any claim that f/f is insulting to them in any way -- much the reverse.
One slash fan writer has written three episodes of the show itself, on the invitation of the producers, who were impressed with her work. The cast have been broadly supportive of the slash, signing such items as artworks. Lucy Lawless has been known to put in appearances at lesbian clubs for her gay fans, and Lucy and Renee appeared at the Sydney Gay and Lesbian Mardi Gras in 1999.
As with Blakes 7, the anti-slash position has been attainted with a sorry list of crimes over the years, including destruction of web sites, verbal and physical abuse and assault and some have been gaoled.
In Xena fandom, it's still possible to have anti-gay beliefs, but you won't be allowed to express them openly on most mailing lists and chat channels. You'd also have to be aware that the opinion of many cast, crew and fans is that your beliefs are (as Robert Trapert said) "beyond contempt".