That's different. If a MM shorts 1,000,000 shares, 10 times during the day, and closes out all of the positions by eod (as usually happens), there are 0 open positions.
But, the daily volume will show the total for the day as 10,000,000 (1,000,000 x 10).
The next day, people misunderstand the number and claim "10 million short yesterday ! Squeeze coming".
So, I am not disputing the raw numbers, but they are misused & abused.