It's not so much the arms flexing as it is the bushings deflecting, allowing torque application to wind the axle up against its bushings, which unloads the tires suddenly, which unloads the axle suddenly, which reloads the tires, which re-winds the axle, which unloads the tires, etc etc etc. And the LCA bushings are only part of the equation, the UCA bushings contribute as well. The quad shocks damp that oscillation of the axle housing, reducing wheelhop.
You can also eliminate it for good by eliminating the ability of the axle to oscillate that way, either by a torque arm or by eliminating all bushing deflection. But by the time you get done eliminating all the bushing flex in the 4-link, you're left with a suspension that won't articulate much except for flex in the body mounts themselves.
Some people get lucky, some people don't. In my case, I had Global West LCA's with spherical bearing in one and and Delrin in the other (doesn't get much less deflection than that), with HD uppers, and I still had wheelhop that only fresh quad shocks would cure.