The interesting thing with all the things you mentioned about Rejection!Tifa, is that's quite a lot of what hardline pinkers have and still do say about her. That she's stalking Cloud in KH2, that she's naggy, that she's clingy, despite the creators taking pains to try and make sure she wouldn't come off that way, etc, and all the other statements.
In a select few cases, I believe they have the rage they do because, well, deep down, they understand they lost. And just not in the argumentative sense, either. I'm speaking of the folks who wanted to BE Aerith, who self identified with her and wanted her to get Cloud because they were crushing on him, and were pissed off that she died and never came back, that the other girl got him.
Same with a lot of Zack haters, I'd bet.
I can't say that for all or even most of them, of course, but I've come across a few who fit that schema in my day, and they tend to be the most reactionary when the ship is threatened.