Leth and Dideriksen were not on the rr list, so could not be selected.
https://sport.tv2.dk/cykling/2021-07-16-danmark-tilbudt-ekstra-ol-plads-men-takker-nej
Maybe it was Fahlin’s spot they were offered, she has withdrawn due to poor form.
Since they were already selected for the Olympics for a different cycling event they would have been eligible.