Jonkster,
I'm not trying to argue for or against any myths or theories, just trying to get the basic physics straight.
An aircraft going downwind at 120kts airspeed, into a 60 kt headwind with 180 kts groundspeed tailwind has a lot more kinetic energy and inertia than one going at 120 kts airspeed into a 60 kt headwind with only 60 kts groundspeed. Compare the braking distances if you try and land off those conditions. The question is so what? When turning downwind that extra kinetic energy has to come from somewhere and over the course of a downwind turn the aerodynamic forces provide that acceleration without drama.
However, someone above suggested trying a loop in a glider into a strong headwind starting with zero knots groundspeed. Try that and let us know how you get on?