Fiona said: "you insist that my views have as much validity as if I had suggested that Avon likes ballroom dancing."
Apart from the fact that we have no evidence either way as to Avon's feelings about ballroom dancing, I fear you are missing the point. Many fans have interpreted, independently, a sexual tension between Avon and Blake. And many have interpreted this as that they were either having a relationship or that they could, and some have thus gone away and explored that possibility in fanfic.
Your view, I believe, is that there was no possibility of a relationship between the two and that they were both heterosexual. That is a totally valid viewpoint and amply backed up by onscreen evidence and the views of the writers and actors. The point is that it is not the only viewpoint.
Why do you find it so difficult to believe that others can have a different viewpoint when all the evidence suggests that they do? Are you saying all the people who say they have made slash interpretations are lying? That would be just ridiculous. It is perfectly clear that many have made these interpretations. You might think they are wrong, but surely you have to accept that they have made them and therefore such an interpretation is possible.
-- cheers Steve Rogerson http://homepages.poptel.org.uk/steve.rogerson
Redemption: The Blake's 7 and Babylon 5 convention 21-23 February 2003, Ashford, Kent http://www.smof.com/redemption