I would describe the distinction slightly different:
Current UY points lose ability to bank after the deadline whether or not they have been used to book a reservation. If they have been used to book a reservation after that will occur after the 8-month mark (banking deadline), they could still be banked if you cancel that reservation before the banking deadline (normally you would also have to do so before 30 days prior to check-in to avoid them going into holding... but DVC appears to still be waiving holding for resort closure cancellations).
When borrowing points, you initially pick a specific date that you're borrowing them for. But, normally, if you cancel that reservation, those points go back into your "pool" of current UY points, available to book with, but no longer associated with a specific date.
This is what is rubbing some the wrong way... that DVC is returning points to their original UY due to resort closure cancellations when those points would normally remain in the current UY. But as some have illustrated, DVC's reasons for doing this may actually be to help solve the inventory balance issue rather than to just "sprinkle some pixie dust."
If all of those borrowed points were going to expire at the end of the current UY, then there might be a LOT of people trying to use them immediately once DVC opens to avoid losing them. By returning them to the original UY (worth noting again that the points would never have been borrowed in the first place if the affected reservations hadn't been possible), they are perhaps spreading out the use of those points across several years to mitigate the overage. Because it's as if those points had never been borrowed, they can also be banked to the next UY, which some people will do and further spread out their use.
I think DVC's analysis may very well be that it's better to spread the effects out over time to "flatten the curve" so they don't get overwhelmed with everyone trying to use those points all at once. Sound familiar?