Fast Google search gives done additional details:

> Tic Tac® mints do contain sugar as listed in the ingredient statement. However, since the amount of sugar per serving (1 mint) is less than 0.5 grams, FDA labeling requirements permit the Nutrition Facts to state that there are 0 grams of sugar per serving.

So? It seems that they're honestly reporting exactly what's required from them and exactly what you need to balance your diet.