Limiting characters can also be a feature, so users can't use emojis in their password (this is so fun), to realize later they can't login, because they don't know how to input emojis from their desktop computer.
Hopefully passwords will be gone soon (at least that's my hope).
Don't get me wrong, it's a stupid limitation indeed -- but sometimes decisions like these are meant to stop users from doing stupider things :)
I'm no fan of oversimplification, but Apple's audience is everyone, not just power users. In that case, I'd prefer having advanced options surfaced to me as "advanced" so I can do what I want, but leave the simple experiences for the simple folk.
You might have half a point about emojis, but that's not what Apple is doing here.
Is there a reason I as a Swede should be limited from using my full native alphabet in my passwords for example?
As an example, you know how people sometimes suggest using a short sentence as a password? Here's a phrase in a local dialect, which means "and in the river there's an island"
Å i åa e ä ö
Notice how only 2 of those letters are available in ASCII.
ASCII only is not a feature, and I honestly doubt anyone would try to argue that it is if this was about any company other than Apple. Try to look past the "who" and focus on the "what".
Hopefully passwords will be gone soon (at least that's my hope).