I don't think all this 'denying the canon' is actually something we can ever understand. I've never been one to support just a fully canon pairing either, I enjoy a lot of fanon pairings. In fact, I like fanon pairings better.
...not that I'm saying Clack is fanon or anything just because I like it better than Cloti.
And you're not the only one bothered by this. I don't think it's immature, as I feel bothered by it as well. Although taking that from a 13 year old may not exactly help as much.
Of course, I do have this urge to deny some canon pairings...like Squinoa. I just don't like them together; I don't like the way they developed their feelings for each other, I don't like their backstory, I don't like their proofz (LOL), and I don't like Rinoa. But even then I'd probably be annoyed if someone said "I couldn't see Squinoa in FF8" or "This scene actually means Squall doesn't love Rinoa" etc. I think it's just stupid. The fact that I didn't act on my urges means I'm avoiding stupid, or sounding like one.
And I always did think that Zell wanted to touch Squall's other "gunblade".
/random
LTDs are pretty lulzy though, and it continues to amaze me at how much some people can take a lot of things out of context, and somehow sound logical. It sometimes makes me think that all of these are just for show. Everyone in the Pink Side are actually just deliberately doing such things to get the lulz out of our reactions.
Am I the only who thought this? Some of these things are too awful to be real. Koispacebito? SRSLY. That was obviously made to get something out of the Dark Side. They're secretly laughing at us.
As for me fighting against the Clerith; I just love the characters individually too much. I love Zack, Cloud, Tifa, and Aerith. If Clerith happens, then what about Zack and Tifa? It's unfair for them. This is saying if Clerith were canon. In fanon, it's okay, because I ship Fack anyway. 8D I just feel that as characters in a world like FFVII, they deserve as much happiness in love as the next person, whether in the Lifestream or no.
Even Sephiroth deserves some lovin'.
Hojo doesn't.
...Oh yeah, I made no sense.