This can't be right. They must have something off with their method.
You can even see murky, starchy white water drain out of the bowl the first couple of times you rinse and stir the uncooked rice. If that's not starch then what is it? The water will come out visibly cleaner with each round of rinsing and stirring.
Sure it could be placebo but I definitely feel that I can tell the difference between unwashed and washed rice.