We're just going to have to agree to disagree, then. To me, it's a very clear and nearly 1:1 correlation to the situation/purpose of Lordran (which didn't feature an exodus either, incidentally. It was never that all people become undead) and there's no diagenic reason to think the curse acts any differently in the sequel.
I think the problem is that the sequel doesn't really tie in its lore with the first game so well because of holes in the narrative. It's obviously designed to leave a lot of room for interpretation, but it kind of seems like the second game was meant to be in a totally different universe, but was later linked together by a few snippets of dialogue because the creators found out a little late that fans were deeply attached to the lore of the first game and expected to continue their exploration of it.
I respect your interpretation, and I don't think its wrong either. I think that the game's narration kind of just stumbles on itself in this area. The reason I mention exodus only relates to the quote you brought up:
"Heh heh heh
What seems to be the ruckus?
Ooh, my! Your face.
The face of the curse.
It's an Undead.
An Undead has come to play. Heh heh
They all end up here, all the ones like you.
You spoke to that kind old dear, didn't you?
...
All people come here for the same reason.
To break the curse.
You're no different, I should think?"
The world with Lordran had an undead curse that affected all of humanity. Some pilgrims went to Lordran in an attempt to end that curse. In the case of Drangleic, only some cursed people seem to exist outside of the kingdom, and as the bolded part of the quotes show, all of them end up going to Drangleic in the end. I mention exodus because if the whole world was cursed, you would think that Drangleic would have a heck of a larger population.