Thanks Brian. That clarifies your meaning. I agree that the pivot design of the front axle's attachment to the chassis
reduces the benefit of loading the front tires relative to side-to-side stability. But it does not eliminate it. Here's my reasoning. The axle is not attached by a perfect gimbal, so even within the limits of the pivot range, the increased mass at the wheels will add a dampening effect not only to the vertical rotation of the axle around its own central axis, but also to side-to-side roll, or yaw, of the chassis. It will also dampen wheel bounce over rough terrain.
The benefit becomes much greater, of course, once the limits of axle-pivot have been reached, as in a severe tilt scenario. At that point, ballasted front tires will reduce the risk of side-to-side roll over. I've yet to hear of a tractor rolling onto its side without both high-side wheels leaving the ground.
Additional side-to-side stability comes from the increased ground reaction force of the ballasted front wheels. This increases tread-to-ground friction (as well as actual tread bite into softer material), reducing side-to-side slippage at the same time that it increases traction in the direction of travel.
I'm not suggesting that we all add ballast to our front wheels. I don't with mine, for my uses. But I disagree that it would do nothing for side-to-side stability.