It's all the levels to K/F, I think. They were friends, then rivals, now bitter enemies, and yet Kamui at least still has feeling for him. Since I don't have any emotional investment in K's personal happiness, I find the ship interesting, at least in theory

Now, if Kamui were a real person, I'd tell him to stay far, far away, go find a nice girl like Yuzu, or a nice boy like Keiichi if he prefers. ;)