Therefore the retreating blades are flapping down with regard to the control orbit even though they appear to be going up with regard to the horizon. How else do you explain the high AoA on the retreating side (which we know is true) and the phenomenon of retreating blade stall?
Think about your basic aerodynamics.
At 90 degrees right, the blade is at its minimum pitch, and has its maximum rate of flapping down. It reaches its lowest point of flapping down at the front, while the pitch angle has started to increase via the swash plate.
At 90 degrees left (retreating side) the blade has its maximum pitch angle, and has its maximum rate of flapping UP. It reaches its highest point on the orbit at the rear, where the blade pitch has started to decrease again, and then back to 90 right where it has minimum pitch and max rate of DOWN flap.
If you need convincing, look at the sine wave depictions of the pitch angle and the blade position, separated by approximately 90 degrees - phase lag.
Because of the huge differences in relative wind in forward flight, the advancing blade has to throw away huge amounts of lift (smaller pitch angles / alpha) to match the pitiful amount produced by the retreating side (with bigger and bigger alpha)- a ratio about 7:1. Eventually, the tiny part of the retreating blade with a positive airflow reaches its stalling alpha, and away we go. THAT is why you have retreating blade stall, not because it is "flapping to equality".
This is why the coaxial counter-rotating blades are so efficient - they can operate with a smaller rotor diameter and higher forward speeds because there is no dependence on the retreating side to produce lift.