Apparently it also applies to pax transiting these airports to the US.
But the document detailing the enhanced security refers to "last point of departure airports" - so if you change planes at one of the affected airports for the last leg of your trip, the rules still apply.
Although with this language it wouldn't apply to 5th freedom flights that transit Europe. So flights DXB-MIL-JFK, etc, aren't caught.
IMHO a poorly disguised economic restriction against 10 airlines. Nothing else makes sense. Perhaps the 10 airports will implement a blanket restriction on all direct (and indirect) flights to the US. That would be reasonable.