Except that the only time that vendor pool would be used outside of tests is when folks build systemd from source on their own. Each GNU/Linux distro overrides those defaults when building/packaging systemd, so the vast majority of users would be entirely unaffected.

In other words, the people who would run into the error you propose are the same people who know fully well what systemd is and is not (and - I'd hope - would know how to read the rest of that hostname and surmise that the issue is with an NTP pool and not systemd itself).