Why do people believe that Beowulf is fiction?

[Mister Agenda]

That's a good point, but usually when the dragons, sea serpents, and/or talking animals show up, I can conclude that it's at least partially fictional.

Really, I've seen dragons and sea serpents on the discovery channel and in science books.   I've also heard animals that can talk such as parrots, or through sign language such as Gorillas.  

Do you dismiss a priori these things that I have seen as fiction?   I suppose that some people do dismiss the moon landing and the holocaust; from what I gather it was mostly based on incredulity.   Do you agree with them as well (or I assume at least justify their method)?

I guess an honest conversation in good faith was too much to ask. I'm about ready to dismiss anything you say a priori as mealy-mouthed weaseling.