Your correct....
However, take for example the pic in your sig, of the Rodeo....
The front left is not compressed, AT ALL....
Imagine, for a moment that, as the front right dropped to full droop, that the front left had REDUCED spring preasure as a result.....therefore allowing it (front left) to bottom out in full compression, while the other is at full droop....
Thereby allowing full utilization of all your wheel travel, not just a couple inches of drop, or compression (as in your photo)