The problem is that "casuals" has lost its meaning. people read casual these days and what they see is "Easy" and its the same with other words like "accessible" people see that and again see "easy". pretty much everything gets seen as easy instead of what it actually means.
Incidentally, I had a NN conversation the other night with someone who thought of "casual" as anyone who did not do the "serious" endgame content (which I basically assume to mean anything at least at the level of ex primals, although it was specifically savage/ultimate that came up in discussion)

I personally don't feel like that's the best definition of the term. Some people, myself included, invest far more time/effort in this game than what can be reasonably considered as "casual" despite not really being a hardcore endgamey type. I don't think casual players level everything to max, for starters. To me casual is more like the kind of player that maybe hops on for an hour or so at a time to get a quest or two done here and there, and probably not even every day of the week. If that was the kind of player I was, I wouldn't be anywhere near the point in the game where I'm at now.

I feel like "midcore" was created as a term specifically for people like myself, but I actually don't hear it in conversation much these days.