There is a point to be made about how they just tacked on their own little subjective house rule to the definition as read.

Fortunately, there's a comic planned for after this one! HUZZAH!

I mean, yeesh, there better be. Susan went on for so long that I didn't have room for a punchline. I mean, do we really need to punch all the lines? No, we don't, but it's preferable in this sort of storyline, darn it!

I do think it's fair that there is an expectation that a fan likes something they're a fan of, though I can see nuance to that. In most cases, I think it will be a case in which someone is a fan of parts of a franchise, and not of others, but we're talking many, many possible scenarios here, including plenty I'm probably not even thinking of.

In any case, Susan does point out there's room for potential exceptions even if liking the thing you're enthusiastic about is most commonly expected.