Ok, I am being a argumentitive.
To use the phrase "when performed properly" IMO states that if you are causing pain you are doing it wrong. I do not think I am doing my techniques improperly because they cause pain. Pain is a part of training IMO. I do not rely on pain as the sole motivation. Taking uke's balance is primary.
yes, it's a matter of perspective. Which is fine. From my perspective it's not doing it properly if you can't move you uke without using the pain element in normal practice. Because I've been dropped without pain in nikkyo, sankyo, yonkyo and I've learned to do that with others my experience makes me inclined to think of a pain as something I add since the throw can be done without it.