It IS the laws of Physics. The moving vehicle in a straight line on a smooth non-crowned road on a still day with a steering system that has little play( unlike my previous Expedition): has little force to deflect it from it's path. Add a strong cross wind: this vector of force will deflect ANY moving object; (ask a trained military or FBI sniper about shooting in the wind). THis is largely related to the surface area relative to the direction of the wind. A corvette will have less reaction than a 15 pass van... a semi is more affected. Other factors come into play, including spring rates, suspension compliance, weight, the boost and intrinsic "stiction" or weight of the steering rack etc. For practical purposes, the cross sectional area is the big factor for a vehicle in the wind.
I believe your large mass wheels aggrevate your complaint. When moving, You have 4 BIG, Heavy flywheels that want to maintain the motion, direction and inertia that they are proceding in.. Big crosswind comes along, deflects the car's intended path and it take more force to correct the cars path. This is also why Dubs slow acceleration and prolong braking distances AND upset handling.... You always have to overcome the extra rotational mass. There is no free lunch!!
I just finished taking two 900 mile drives in windy winter weather. Did the car move around in the wind? Sure did. Was it as bad as the same trip to visit relatives done in the Expo? Not even close. I'd suggest you get an alignment done, and I'd try a windy trip without the dubs.