Metro-style apps, metro-style desktop/explorer, metro 360 UI, metro start screen, metro-style microsoft.com
Leaving everything labeled as "metro" creates more harm in the future as Metro will start to (if it hasn't already) be defined as the lowest common denominator between all these various interfaces (flat buttons, simple icons, etc). It loses its meaning, and then it gets really confusing when people start associating UIs that use the metro design philosophy with Windows 3.1 because of a constructed, incomplete definition.
It's also better to maintain this separation of implementation from design language to encourage people to deviate from the usual implementations. We don't want all platform interfaces to look exactly the same: they should meet your expectation to an extent in that they should follow the same interaction principles and guidelines, but they need not have flat, colorful squares.