The throttling here was so bad, the phones were completely unusable during the throttling. Sure, the operating system was running but doing basic tasks like using Apple maps or even sending a message would be effectively impossible. Imagine trying to play a video game at 2 frame per second. Unusable.
The real decision was that Apple didn't want to pay for millions of battery replacements, so Apple came up with a "software" fix for a hardware problem... Except that the software fix made the phone unusable.