No, as it clearly says in the article, there is a difference in tariff rate. If you dig down to the actual tariff schedules, you will see that women pay a higher tariff rate for underwear even when it is made of the exact same material category as men's underwear. There are literally seperate Harmonized Tariff Schedule codes for men and women's underwear (same thing applies for many other types of clothing, e.g. coats).