There's a bit of peer pressure at work here, probably.

Oh, remember back when that "unpopular opinion" meme was making the rounds and a lot of people seemed to define that as "opinions a lot of fandom has anyway"? (For example "I don't like the lead, I like the sidekicks and the morally ambiguous characters" - no, gasp, REALLY?) I made an effort to think about some opinions that I knew were genuinenly unpopular, such as "I like Anakin Skywalker, and I don't mean as Darth Vader, I mean as Anakin, starting with the kid" - and this was before Return of the Sith, when he was the most hated character since Wesley Crusher in sci fi fandom - and this felt ever so liberating. Go for it, don't disclaim, I say.

And, as you say, it hugely depends on the fandom: I haven't seen that much Adama/Apollo fic yet.

I haven't seen any, but I saw some summaries for Lee/Zak, I think. Only two or three, though.

At the same time, I definitely feel sorry for any SPN non-incest or - shock! - gen fans. Of course, the latter might be the fan equivalent to Nessie.

I know at least two: vaznetti and hossgal, so they do exist...