As to Graham's point about anime coming into being second, what's the point of pointing out that anime originated from western animation? Yes, that happened, but does that superior determine quality? No, and besides, we wouldn't be having this discussion if we didn't feel they branched off in style at some point. Rock music owes its creation to Jazz: Does saying "Jazz came first" stop all arguments over which is better? I don't think so.
As to Kyle's argument on the mass appeal of both mediums, I'd say is also irrelevant. Every piece of entertainment is something that audiences "...are hooked on, or couldn't care less about." I think Football (of the American variety) is incredibly boring sport, and that I couldn't be bothered to watch the superbowl, despite it being one of if not the US's most popular event. By Kyle's argument, I can't ever win a debate about Football being boring because I am in the minority in my opinion, and it is not "normal". All fanbases also have tiers that separate fans, as I'm sure somewhere a older Eagles fan is chastising a younger fan for his lack of knowledge because he has been watching Football for 15 more years than him, and watches other team's games, unlike his younger counterpart.
I think I finally understand where Dan comes from in his dislike of anime, and that is a finite amount of detail. Most anime, for Dan, is far too detailed, and thus, far too distracting, for Dan's visual aesthetics. When Mr. Freeze narrows his eyebrows, Dan knows he's angry, and that's enough. In anime, when Goku narrows his eyebrows, veins bulge around his eyes, he screams, and then is enveloped in a red glow, it's over-the-top for Dan.
The other reason, I'd guess, is because Dan wants his entertainment to be relateable. There's a cultural divide in all anime, with some cues being more specific to Japan than being something American or universal, and also in his own examples of 12 oz. Mouse and Aqua Teen Hunger Force, where cultural trends and normalcy are ignored in order to present something ridiculous.