Why not use: "systemctl stop "?
Thanks for the helpful hint. I didn't know about that until now. (now I'll have to figure out what name my display manager is known by to systemd -- is there no end to the rabbit hole?) I'm still not sure, though, why systemd couldn't have left backward-compatible aliases around -- even if they spit out 20 caveats when you use them, including what commands I probably want to run instead. The command you suggested is shorter and more reasonable than what I figured out to use, but it's still way wordier than "killall gdm" or "telinit 3".
Also, I'm posting as me. Can you please do the same?
Also, I'm still not happy adopting an init system whose authors treat corruption of the journal as a "won't fix". Not happy at all. That's not an attitude that inspires confidence and I don't understand how any putative improvements in other areas out-weigh it, never mind the silly ones I've heard like "lower PID numbers!", "lower socket numbers!": yeah! as if that sort of stuff ever mattered.
To others: slackware will get my due consideration as will gentoo and alpine. Don't count on BSD escaping this nonsense, though. I understand Apple is pressuring Darwin to adopt a systemd like system there, too. Why, oh why!!?