Because it was a game that is supposed to give a reason to the existence of a 3 well established characters and did it poorly. Well other games like OoT and ALttP talk about them in past events, Skyward Sword gave them a starting position and failed to pull it off. This also makes even less since since Minish Cap comes after the timeline which makes the forging and the Master Sword even more of a strange event in that game.
What was done poorly? Zelda's powers are finally established as coming directly from a goddess, one whose specific job it is to guard the Triforce, no less. Link's powers are established as coming from his devotion to said goddess, which is
pretty much exactly where heroes are supposed to get their virtue and magical abilities in every hero myth ever. If anything, it's Ganondorf who got the shaft, since TWW hinted at some complexity behind his fall to evil and SS suggests it's because an ancient demon wants to use him as a pawn in his power struggle.
The history of the world that you're a apart of. It's clearly an established land with it's own history.
Did you think that the gods just plopped down some people called Hylians in Hyrule and say "here you go, this is Hyrule, and you live here"?
Of course the land had a history that predated the kingdom of Hyrule and its settlement by the people who owe fealty to the royal family. Even Twilight Princess alluded to this.
Yeah but I'm only talking about SS since it's the first in the timeline and attempts to give meaning to many different staples of the Zelda series at once.
LttP was the "first in the timeline" when it released. It explained where the Triforce came from (created by three gods), where Hyrule came from (settled by the people chosen by the gods), where the long ears of the Hylians came from (given to them so they could hear the voices of the gods), where the hero came from (hero prophecy), where Ganon came from (human thief Ganondorf who attempted to steal the Triforce), etc. etc. It also introduced the Master Sword, Kakariko Village, Lake Hylia, the western desert, and many other series staples.
OoT was the first in the timeline when it released. It actually showed the origins of Kakariko Village (Sheikah village), the Triforce (with the creation cutscene), of Link's tunic (Kokirish clothing), the sages (a multiethnic line of magical beings, descended presumably from an even ancienter line of beings who created the Temple of Time and the Master Sword), and introduced the races, the idea of the Triforce being split when someone touches it, etc.
SS shows what Hyrule was like before the kingdom was established, what happened to the Triforce before it was sealed in the Temple of Time, how the Master Sword was created, how Zelda got her powers, and (supposedly) why Ganondorf appeared. It also introduces a bunch of pre-Hyrule races.
I don't see what's so different about SS, other than that it didn't meet your fantasies of what Hyrule was like pre-kingdom.
When you make an origin story, one of the worst things you can do is make people question more about the game/media that causes contradictions.
Ocarina of Time, The Wind Waker, Twilight Princess, and A Link Between Worlds all contain more egregious contradictions than Skyward Sword.
OoT outright contradicted the accounts of the war to seal Ganon as told in LttP. In LttP's story, there was no hero who appeared to save the land, Ganon got the entire Triforce (and still had it by the time of LttP), and the sages were all human old men. How did Ganon wind up with the entire Triforce between OoT and LttP? It was never explained when OoT came out.
TWW contradicted the
aftermath of the war to seal Ganon by creating an entirely new divergent story where Hyrule was destroyed by a flood. This was so irreconcilable with the OoT-LttP timeline originally established when OoT released that they had to invent an entirely new timeline with a BS justification just to get LttP to still fit in the game's story universe. None of this was explainable when TWW came out; they had to introduce the idea in Hyrule Historia, or fans had to assume that it was just another legend and legends sometimes contradict or diverge from each other.
TP straight up handwaved the entire child ending of OoT by saying "oh, Ganondorf got the Triforce anyway, even though you prevented him from entering the Sacred Realm." This still hasn't been explained, by the way.
ALBW attempts to reconcile the story of LttP with the story of OoT by introducing multiracial sages, but then for some reason the Triforce is presented as split up between Ganon, the hero, and Zelda, even though this is not at all the case in the original LttP-LoZ-AoL timeline - the Royal Family keeps the fully united Triforce after the events of LttP. How did Ganon wind up with the Triforce between LttP and ALBW? It's never explained.
SS contains no raw contradictions.
- There's no reason why the hero prior to TMC had to wear a hat; SS never establishes hats as a prerequisite for heroes. Even TMC doesn't really establish a "rule" as much as it establishes a cute little fairy tale "origin" for the hat. In TWW/TP, the tunic is specifically defined as having previously been worn by/belonged to the hero of legend (OoT Link, in the context of both stories, who wore it as a Kokiri). So if anything, TMC already screwed the idea of in-universe continuity behind the hero's garb to hell even before SS came along.
- The Master Sword is implied to have been recreated from a less powerful state (it's called the Master Sword as if that name existed previously), and the SS manga shows it being used prior to SS; there's no reason why seven ancient sages couldn't have still forged it as told in older media.
- No one ever explained why Link/Zelda/Ganon always incarnate to battle over the Triforce. So SS talking about this contradicts... what, exactly?