I’m not convinced this statement is true. If you look at the camera properties while zooming in parallel projection, you will find that it changes the scaling of the view frame in model units but does not move the camera (neither the GUI nor the Ruby API exposes the clipping plane location, but visual evidence as seen in the clip below suggests it also does not move). Changing the view scaling makes things look bigger or smaller, which creates an impression of nearer or farther, but that is not what is really going on! In parallel projection, because the entities project to the view along rays perpendicular to the view, camera distance has no effect on visual size! As a result, once clipping happens (usually as a result of orbiting, not zooming) you can’t get rid of it by zooming out.
By comparison, in perspective projection zoom is accomplished by moving the camera closer or farther from the model contents (again, you can verify this by checking the camera properties). Because the projection rays diverge, moving the camera also causes scaling of the view to change, but it is a consequence rather than the controlling factor. In perspective, clipping produces the impression that you have moved inside the model by getting too close to it. Sometimes that’s what you expect, but not always.
I think that in both cases the real problem is that SketchUp seems reluctant to recalculate the clipping plane location as you manipulate the view.