gnome developers claim that gnome is a single block and actively fight splitting it into packages. They'd rather have one single "gnome" package containing all of it.
I've used GNOME for a long time and never seen any sentiment like that. You'll also note that the GNOME project is split across many, many dozens of repos and isn't one enormous monorepo. I've also never seen a distro that demands you install all the GNOME core apps. There's always a metapackage for just the basics as well.
Where's the evidence that upstream cares? Many package maintainers are also upstream project maintainers or contributors at a minimum. I may be "just" a user but as a user of the unstable version of my particular OS I've submitted my fair share of bug reports, both to the package maintainer and upstream, and maybe I'm hitting some sort of lottery but more often than not, there's overlap. I guarantee you that GNOME Calculator's devs don't have a care in the world whether a metapackage in some distro that includes their software has a hard or soft dependency on Network Manager. There is no upstream for a metapackage.
Are there any sources for this? I have a hard time believing that GNOME devs actively fight distros to make *checks note* gnome-boxes a required install on GNOME desktops.
That's not what's happening in this report. This is answering the question of whether an all-encompassing metapackage should prefer to match upstream or integrate more with Debian's philosophy. "Upstream only tests with NM and only supports NM for some features" vs "if it's not a hard runtime dependency, it's a Recommends or Suggests, not a Depends." It's packaging trivia. Decade-old-plus packaging trivia for a single distro. You can install gnome-calculator without any of the rest of the GNOME shell so this is a horrifically disingenuous comment you've got here.
No, just actually represent the situation accurately in what's supposed to be a good-faith discussion. Maybe provide any evidence of the claim you're making. It'd be appreciated.