I mean, I'm all for fans exploring all sorts of stuff. I'm all for people writing fanfic where characters who hate each other in the original work get it on, because writing (and other things) is all about playing around in a massive sandbox, not limiting yourself to what people expect or what is within borders of The Common Sense. Heck, my fanfic writing didn't even get anywhere near anything resembling good before I wrote a small post story of how one of the characters killed the other (and then themselves.) I have loads of written horrible not published stuff that will never see the light of day. It was all experimental. Ways of trying to bend the understanding of a character, ways to get from A to B, ways to write things where you'd think 'nah, this wouldn't fly in a millions years, but I'm up to the challenge to see if I can come close.' So Cloud and Sephiroth, sure. Show me a good written fanfic that convinces me it could be a thing, I'm all up for it.
So I'm like, hell yeah Cloud is closet bisexual for Sephiroth. In a million universes and a million settings and in all kinds of imaginable (and unimaginable) ways, Cloud is definitely a closet bisexual for Sephiroth. Do I think canon supports it based on the obsession thing? Not really. But it's something for shippers to pick up on. You obsess with someone? You must be attracted to them in some way or another.
Me, I imagine bisexual Cloud feeling drawn to Sephiroth from the moment he got to know him, ending his obsession (in that way) when he found himself too often waking up drowning in his own sweat from dreaming he made love to him and then murdered him in the most grusomme way. Then to push all of that away along with realising his true persona.
Why did I stop writing fanfiction lol