So, first of all, this is a GNOME "bug", not a Debian bug. It is a GNOME metapackage that depends on one of the web browsers (specifically, "gnome-core"; see below), not "Debian" as a whole - you can install other DEs - and Mozilla has nothing to do with it at all.

$ apt source gnome-core [downloads meta-gnome3-3.38+3 on Debian 11] $ cat meta-gnome3-3.38+3/debian/control [...] Package: gnome-core Architecture: linux-any Depends: libatk-adaptor (>= 2.38), at-spi2-core (>= 2.38), [...] firefox-esr (>= 78) | firefox (>= 78) | chromium | chromium-browser | epiphany-browser, [...]

This is done, presumably, because anyone using a desktop in 2022 expects there to be a browser installed, and the GNOME team knows this - the dependency list here is the two biggest and most common (FLOSS) browsers, and GNOMEs own Webkit-based alternative. The ordering there is also why it prompts to install chromium first when removing firefox (or vice versa). And yes, it doesn't happen on servers because you don't (if you're anywhere close to smart) install DEs like GNOME on a server.

If you really want to go browserless though, it's quite trivial to purge these packages out and not break a normal GNOME desktop simply by removing the metapackages as well (see below).

There is one other thing though with a standard "task-gnome-desktop" intall that depends on a browser: LibreOffice's help, which I presume is entirely web based and thus would like to launch a browser as a dependency, but even this can be removed safely and easily (and if you don't, it will just install the Dolphin file manager, which may have web browsing support built in - I'm not sure because I don't use it. I'm simply showing removing this too because otherwise, there's a lot of lines of Dolphin dependencies that make it hard to see the point.)

$ apt remove gnome gnome-core task-gnome-desktop firefox-esr chromium chromium-common chromium-sandbox libreoffice-help-en-us Reading package lists... Done Building dependency tree... Done Reading state information... Done The following packages were automatically installed and are no longer required: gnome-remote-desktop gvfs-fuse hyphen-en-us libreoffice-help-common libu2f-udev libvncserver1 mythes-en-us node-normalize.css system-config-printer Use 'sudo apt autoremove' to remove them. The following packages will be REMOVED: chromium chromium-common chromium-sandbox firefox-esr gnome gnome-core libreoffice-help-en-us task-gnome-desktop 0 upgraded, 0 newly installed, 8 to remove and 18 not upgraded. After this operation, 476 MB disk space will be freed. Do you want to continue? [Y/n]

This author here is retarded and is trying to make a mountain out of a molehill for unclear reasons, by heaping blame on random parties (Debian as a project, Mozilla which clearly he doesn't like despite them being the only reasonable alternative to Chrome and its derivatives) instead of the actual "guilty" party (the GNOME team). And I use "bug" at the start and "guilty" here lightly, because as you can see it's trivially easy to work around this with even a cursory knowledge of Debian's dependency system ("apt-cache rdepends" is your friend here).

As to why this doesn't happen on Ubuntu, I can't say, because I don't use Ubuntu. But given that the dependency tree of "task-gnome-desktop" -> "gnome-core" -> a browser is a Debianism, I would presume Ubuntu simply does not have such a metapackage and thus does not try to enforce it. That's not really a dig at Debian or plus for Ubuntu, they simply do things differently in terms of this particular dependency tree. And given how much shady shit Canonical has done, trying to praise them as some noble alternative to Debian (an actual community-driven project) because the author doesn't know what a metapackage is, is laughable at best.

Edit: I completely forgot this gem:

“You could at least ask the user if they want to bring in “epiphany-browser”,” Ryan noted.

It will literally do that if you tell apt to "remove" both firefox(-esr) and chromium-browser, because then it gets down to the 3rd option in the dependency list, which is epiphany. To elaborate on what I said earlier, Debian dependencies are always preferred in order: so firefox-esr > firefox > chromium > chromium-browser > epiphany-browser. To get to the bottom of that tree you have to explicitly tell Apt to "remove" all the options above it, otherwise it will try to be smart and helpful and just install the next best option. Again proving that this person has no clue what they're doing but still feels compelled to cry "wolf!" about it.