[e7620]

> GNOME doesn't rely on systemd, it wants an API

The problem is the following: GNOME depending on GTK+? Just an API.

Of course, it's not your fault, the problem is systemd developers don't want to separate the components as individual programs. So if you want to use logind you also have to install the whole systemd, requiring linux to boot. (pun not intended)

[the_why_of_y]

There is a difference of several orders of magnitude in size and scope between the GTK+ API and the logind DBus interface.