That is correct, David.
Patch Manager is built on top of the Microsoft WSUS platform. The Microsoft WSUS/WUAgent engine only provides patch capabilities for Windows operating systems and the applications that run on Windows. As such, Patch Manager provides only patches for applications that run on the Windows operating system. The Table of Third-Party Patches only provides information on third-party application packages, because we do not package OS updates; those are obtained direct from Microsoft via WSUS.
Mac OSX and Unix/Linux patches are not available via Patch Manager.