: Well, technically for as much as the novels in the XIII series are called to be "supplemental material" they are very much an integral part of the overall story. Sure each game has, in a manner of speaking, its own story, but in the long run they do come together into one single narrative by the end of it (with the novels, details in the datalogs, retcons and everything that happens in between being canonical). And yes we are all aware that are fans who don't like that or don't care about it at all. But this is one of those "it is what is it" cases. *shrug*
With the Compilation of FFVII on the other hand, that has always worked as a way to take liberties with the universe that was established in the original game's narrative. However, the remake is (for better or worse) the perfect moment for the team working on this to bring all of what they did in that compilation into the main story of VII. And with Kitase, Nojima and Nomura being involved that could potentially happen in order to bring a breath of fresh air into the story hardcore fans know by heart.
So why is everyone so mad?
In essence many fans of VII wanted out of the remake what Zelda fans got with Ocarina of Time 3D, but in high-definition and in a single release (or installment like Kitase calls it). Instead what's happening with this remake has parallels to what went down with StarCraft II by making the campaigns of each race its own release that would later form a trilogy unlike how the original StarCraft and, its expansion, Brood War offered the campaigns of all of the races in one package.