The metaphor doesn’t work. It’s not like saying “hey, you can’t use Strixhaven in our Forgotten Realms game”. It’s like having new pages show up in the Players Handbook automatically. These aren’t options players select, they’re added automatically. So players feel like of course this stuff is allowed until a DM has to explicitly exclude it.
This is the reason so many
complained about Silvery Barbs. It wasn’t because the spell itself is busted. It’s because anyone who had it didn’t even remember what book it was from and DDB didn’t have (and doesn’t have I don’t think) a good way for a DM to filter material at the book level.
So now WOtC is adding lots of new stuff and thr DM is the bad guy for saying “yeah, no”.
I’m glad you have no problem with any of this. I do and so do many others.