"just about fiction"

I can't figure out the purpose of the following exchange, which took place last Saturday -- Young Man with Clipboard outside Amoeba: Can I ask you a few questions? Me [defenses down, for some reason]: OK. YMCOA: Do you ever read fiction? Me: I've been known to. YMCOA: What genres do you read? Me: I guess I mostly read contemporary and classic "literary" fiction. [Not exactly accurate, and I'm not sure I've named a genre, but it seemed like the answer that would make the most sense.] YMCOA: Any mysteries, science-fiction, things like that? Me: Some science fiction, off and on, that's about it. YMCOA: What attracts you to science fiction? Me: Oh, I grew up with it, so every so often I check something out -- not as much as when I was a kid. [Again, there's a longer/better answer, but I'm not feeling that I need to bring my A game.] YMCOA [consulting his script]: Do you know why the '30s and '40s are called the Golden Age of Science Fiction? Me: Because pulps like Astounding and Amazing were in their heyday, and writers like Asimov and Heinlein were establishing the genre's conventions. YMCOA: All right! What do you think of L. Ron Hubbard? Me [penny dropping, rueful smile]: I think he was a respectable fiction writer, but I'm not at all interested in Scientology. YMCOA [also w/ odd smile]: It's okay, this interview is just about fiction. So, have you read anything by him? Me: Probably some of his old short stories, a long time ago, but not Battlefield: Earth or anything recent. YMCOA: All right -- thank you for your time.