I think there are some things that have stayed in the game that both the creators and fans have agreed is a crucial part of the game, that is kept in because that's how it's always been, that could probably be looked at again and changed. It's been a long time since most of the systems were created. But there's basically no convincing them that it is anything but perfect, to the point where giving you the option to change one questionable design decision mocks you as only being a Casual player.
I'm trying to think of a good example...it's kinda like the people who love Mega Man II so much that they hate the slide and charge that was added later. If the games were designed the same but those two things were gone, that's what I feel FE is like, more work than it should be when other options exist. If the later MM games added in sliding and charge but you had to select Baby Mode at the start to use them, that's how I feel about FE's attempts to update and modernize.
Now I'm trying to remember the game where playing on Easy actually gave your character something like a pacifier and rattle, and annoyed that I can't.
Is there some background here, like an interview where the creators said that people who didn't like perma-death were stupid or something? Because otherwise I think you may be reading a bit too much into the word 'casual.' Why is it that your first instinct to the word is to assume you're being mocked?
To me, that just conveys that it's a mode for players more interested in story/ not as interested in the more punitive aspects of the game.
Good on you for playing through the entirety of FE:A before drawing a conclusion, although I don't think you should have forced yourself if you really didn't enjoy it.
The fact that there is a readily available mode for the game which addresses almost all of your complaints (perma-death, lack of tutorials, etc) is pretty frustrating, though! Did you really just not choose that option because you thought the developers would somehow think less of you, or what?
I've always had terrible item luck, but it's never been worse than this week.