Did... he just say that Yuji Horii is a bad writer? Because he dislikes some of the small stories that you encounter along the way. Those ones are the result of a lack of writing skill.
Keep in mind this is about the English translation, which is in fact a bit uneven.
So, if I conjured ten previously-nonexistent people into existence beside me, and every single one of them swore that they alone were not conjured, that they had been standing next to me for hours, since they walked into the room, they have pasts and lives and memories... each one of them says it's the other nine people who just randomly popped into existence, that's contradictory? Conjured people shouldn't be able to see the magic but believe it's not happening to them?
He's saying that if you make all these islands reappear in the past, they should have been there for a long time in your present and people shouldn't be surprised that they are there.