I think the gp is complaining specifically about the "OS" bit; that makes it sound like a new operating system rather than a derivative linux distribution

The points are are the same specific topic. A distro is a superset of the OS bit and the latter is rarely distributed without the additional software, documentation, and configuration that make up a distro so, to me, it's more than fine to me to include OS in the name. Even to switch between one Debian derivative to another it's extraordinarily rare to not reinstall the OS as part of that swap, so why not name the whole solution according to what it includes?