I feel that Cloud X Tifa shippers are more accepting of the other side when it comes to LTD. Why is that? Do you suppose?
Short version: Because Aerith is dead, and Cloud wasn't himself, that means that Cloti works whether Cloud liked Aerith or not.
Cloud could have loved Aerith more than anything in the world, but the fact that she's dead and he wasn't himself means that it really doesn't matter much. Clerith doesn't have that blanket, they need to convince you that despite Aeriths death and Clouds broke psyche, he STILL likes Aerith more.
For that to be reasonable, they require him to like Aerith more to an absurd degree, to the point that any romantic feelings towards Tifa would ruin it, because they understand, if Cloud has ANY romantic feelings towards Tifa, then after spending a few years together, he won't be thinking about Aerith. Which is unacceptable to them, because they apparently want Cloud to be miserable, never move on, and keep living in a fantasy world. They want everything that goes against the themes of FFVII. So in a way, they've declared war on FFVII, on it's plot, on it's themes, on everything. They're in the position of both loving FFVII (how they think it should be) and hating FFVII (how it is), and in war, you entrench yourself.
The famous quote, from this site: 'In order to prove Clerith, you need to fist disprove Cloti' still rings true to this very day.
The end result being you have those less vocal Cleriths who just like Cloud and Aerith, but acknowledge the story sets up Cloud and Tifa, but you also have that very vocal disgruntled group who feel the need to defend what they percieve as the original canon ship. The more time and energy they sunk into the argument, the more they were unwilling to accept the argument they were defending was wrong (I'm not saying shipping Clerith is wrong, just yelling about them being canon is).
Basically this.
About young Tifa, I don't think it's been portrayed differently form the OG, Tifa was ALWAYS open and wanting Cloud to join, Tifa was just like that to everyone, it's Cloud's own behavior that prevented it, like he says in the OG, it wasn't Tifas fault, he was the childish one. The "are you ignoring me" line shows that, that's Tifa extending a hand, and Cloud not accepting it. Not because he didn't want to be Tifas friend, but because he wanted her for himself.
Tifa sees their relationship the way she tries to treat Cloud, friendly, because, from her point of view, that's how she interacted with him, and therefore, how she remembers the interactions. She always had friends around, so the 10% of the time she might have been hanging out with Cloud, she perceived as positive, because she didn't want anything from him, but for him, he was 90% lonely, and he wanted more. So the differences in experiences aren't to be marveled at, plus, the events that happened after also colored her memories of course.