Offers to delete system users along with the root filesystem
Accountsservice will, by default, use Fedora-specific heuristics to detect for
UID_MAX > UID > 500 that UID is in fact a human user if it has a valid login shell.
Valid login shells are a valid use case for some system users, e.g. the "git" user, but accountsservice will nevertheless suggest them as a valid user to manage and possibly delete. It also comes with a flag to delete the user's home directory.
It is fairly obvious that if the home directory is "/", this should not be deleted, and most likely this is a heuristic that the account is a system account and not a user account. And if not, then even after deleting the user account, there is no way it should be deleting that particular home directory! This is problematic, because using common Desktop Environment control panels to manage user accounts do not warn the user which directory they're about to delete. Maybe they assume that accountsservice would not offer to manage the user account if it's got a funky home directory that doesn't belong on a user account... (I tried with cinnamon, I assume the below linked Gnome issues would not have happened if Gnome does implement its own warnings.)
I'd also recommend making this heuristic opt-in rather than opt-out, unless there's a particular reason to think most distributions have migrated from one UID_MIN to a new, higher one. Even then, I'd suggest it is better for distros to explicitly enable it in order to properly manage user accounts, rather than needing to explicitly disable it in order to fix the problem of improperly managing system accounts.