They didn't mention cross-OS shortcuts, though. I interpreted "across the operating systems" as meaning "across the various versions of Windows". Yes, Windows is more consistent with their own common shortcuts. But Macs have exceedingly consistent shortcuts across Mac applications, compared to my experience with Windows and especially Linux.

I might also point out that Mac had keyboard shortcuts before Windows existed, so it's not really fair to describe them as the "different" one when MS chose their own, different shortcuts for Windows.

Apple also invented their own key “Apple” now “CMD” for operation like copy / paste to explicitly not have the issue to overload the already know escape sequences. Windows being on a system without a normalized keyboard had to reuse keys that are common to keyboards used back then. Vertical integration played into apples cards even back then.