You're right that the pairing doesn't exist in canon, but the characters still do. Generally if one likes a pairing, it's because they like their interaction, or think their personalities would mesh well, or because they have a lot of subtext, etc. But since you haven't read the manga, you don't know whether the fanworks you've liked are IC, or how you would interpret their relationship. What if you read the manga one day and realize you don't even like one (or both) of the characters? Or if you think they have no subtext?

I dunno, I just don't get this kind of attitude at all. I can sometimes enjoy fanfic about series I haven't watched, but in those cases it's because the writing is particularly good. I wouldn't call myself a fan of that pairing or series; just of the writing. It might as well be original fiction.

But whatever floats your boat, I guess. If you're having fun, good for you. :)