It is cool that there are workarounds and it is much appreciated that people are willing to come up with them and contribute them here, but, to be honest, as a long time pod 2.0 and XT user who just recently upgraded to the HD desktop, I am surprised and disappointed that Line 6 has not taken ownership of making auto import work across compatible devices.
The internal hardware and firmware of the desktop, 500, and pro units are virtually identical and it is absurd that there are three separate editors and a convoluted import process given the value that a seamless import capability would provide to their customers. The 2.0 and XT lines both supported auto import of patches and a unified editor for related hardware and it is disconcerting that Line 6 has not addressed this given that these are no longer newly introduced products and are the mature core of their modeling technology.
In fact, overall, my first impression of the HD is that the editor/software and firmware are actually not nearly as well thought out or "finished" feeling as the XT was even though the units are up to a 2.x revision... aside from the pretty UI graphics, the entire thing feels like a beta/unfinished product and does not meet the standard Line 6 has set for itself in previous products, which is incredibly disappointing for a long time fan/customer.
So, really, IMHO, the poster's original question of "why" it is like this, and more importantly, if it will always be like this, should be addressed by L6 since they have clearly overcome this limitation on their legacy units and they are no longer meeting that level of capability with the HD.