Namibian athletes disqualified from 400 meters Olympic race

The link is here: https://www.reuters.com/lifestyle/sports/athletics-namibia-contenders-withdrawn-olympic-400m-race-2021-07-02/ Namibian juniors were disqualified from competing in the 400 – 1600 women’s category due to their testosterone levels being too high. Looks like that doesn’t disqualify them from 100m to 200m races? If someone is more knowledgeable about athletics and knows why, I’d like to know why. The article caught …