I guess it's time for me to learn #systemd properly. Just wasted half an hour trying to figure out why /home gets auto-mounted when I SSH into the box; it shouldn't be, because I commented it out of /etc/fstab.

Turns out systemd has a "mount unit" for every configured file system, and when you edit /etc/fstab, you're supposed to run systemct daemon-reload for systemd to apply the change, otherwise it'd stubbornly restore the system to the state it believes correct.