1. Once upon a time, cars had no software and no OTA updates. If there was a serious defect it had to be returned to a dealership for the defect to be rectified. This was a recall, i.e. an official order to return to a place. The NHTSA has the authority to require and coordinate recalls.

2. Then cars got software, but had no OTA updates. If there was a serious software defect, the car had to be returned to a dealership for them to install a software update. This was still called a recall - you still have to take the car back to the dealership, after all, and the NHTSA is still involved.

3. Then cars started receiving OTA software updates. As 2. established that a software update for a serious defect is called a 'recall', and the NHTSA is still involved through their recall-coordination authority, this is still called a recall even though the car doesn't have to be returned to a place.