Ok, thanks! You're right, the kernel should probably issue warnings only on mounts, not remounts.
* Any idea why those warnings started to appear only after recent systemd update? * Is masking systemd-hostnamed.service a valid solution to prevent log spam? At least until the kernel developers do something about those warnings. (I don't think i'll ever need systemd-hostnamed.service, my machine's host name is very static: -rw-r--r-- 1 root root 10 31. Jan 2010 /etc/hostname) Anyway, feel free to close this bug.
