A gyro precesses if acted on by a couple. Not otherwise.
Angular momentum is a red herring?
Try stopping a spinning bike wheel with your tongue!
The angular momentum of the disk is what it is, whether it's a solid disk or a series of spokes. To change its direction needs a couple applied normal to the angular momentum and to desired direction of motion. If you swing a bolas around your head, it's not easy to change its plane of motion.
For a helicopter, I'm quite happy that this couple comes from aerodynamic forces on the individual blades and not torque from the control rods, but in order to redirect that vector a couple must applied, and there is going to be a reaction force at the hub, as well as the standard transmission of the life and thrust forces to the body of the helicopter.