Bill Zebub
“It’s probably Matt Mercer’s fault.”
It's just the default. When my friend ran his desert campaign (which was survival oriented), he went through and removed spells that didn't fit his campaign (goodberry, create water, etc). And we played a fun campaign that went at least to 13th level, maybe higher (although the survival aspect was a bit tedious at times).
You have to have some kind of a default after all. While I realize that old-school gamers would likely prefer a more old-school default, IMO this was the better design choice WRT the game's popularity.
I think the problem with that approach is that there’s no official guidance to back up DM fiat here. If you remove those spells you look like a mean DM. In my group that would be ok; I think reactions would range from “that sounds like fun” to private grumbling. But the impression I get on this forum is that at many tables that would lead to arguments and resentment.
If there were official guidance on what classes/subclasses/spells/rules to include or exclude based on setting, the DM could say, “We are going to play (setting type); use the standard list to see what options are allowed”. I for one would find that useful.