I am saying GNOME is primarily a Linux desktop environment, developed practically exclusively by Linux users and thus it makes sense for it to make use of Linux

I am saying GNOME is primarily a Linux desktop environment, developed practically exclusively by Linux users and thus it makes sense for it to make use of Linux specific features, just as it makes sense for FreeBSD technologies to take full advantage of FreeBSD-exclusive features. Just because GNOME wasn't using systemd in the 90s when systemd didn't even exist does not mean it should not use it ever, even if it makes sense for GNOME devs to do so now.