Are you one of those people that doesn't realize that Scrubs: Med School (aka 'Season 9' after it flopped and they had to try and push the DVD sales) was a spinoff?
When you have a different core cast, different plot, and different setting / timetable than the main series, it's a spinoff, and is not something that should contain plot information vital to the main series. So I'll ask you a few questions. Do the two games you mentioned star Sora, Donald, and Goofy? Do they take place as direct successors timetable-wise to KH2? Are the plots direct continuations of the events of KH2?
Perhaps you can provide examples of other venerated series where such vital information is handled by series entries that are not designated as part of the main series? Will I suddenly find myself lost in A Song of Ice and Fire if I haven't read Dunk and Egg? How about Harry Potter if I have read Fantastic Beasts? Some examples of other series that do this would be nice, wouldn't want to think that Nomura is just making up his own damn rules of story structure or anything.