Well, they are razing a great swath of entities created by some of the founders of Marvel, like the Living Tribunal, Eternity, the Celestials. They don't seem to want these creations around for the foreseeable future, and perhaps ever.
I mean, these characters will be back, obviously. Yeah, they're some of my favorites too, but if Marvel can ruin other classic deaths (Like Bucky, Elektra, Captain Marvell, etc.) and people can get over it, what's the difference with this? Almost anything in comics can be undone. Killing off characters hardly ruins the Marvel Universe, and if the direction is unpopular, then they'll just change it back.