Because case law and precedent don't give the CDC the authority to force people to wear protective equipment on private property.
Since you didn't read it, here it is:
That law allows the CDC "to make and enforce such regulations" deemed "necessary to prevent the introduction, transmission, or spread of communicable diseases from foreign countries into the States[.]" To achieve this, the law says that CDC can utilize "inspection, fumigation disinfection sanitation, pest extermination, destruction of animals or articles found to be so infect or contaminated as to be sources of dangerous infection to human beings, and other measures[.]" The administration, the judge noted, has claimed that the mask mandate falls under "sanitation."
Since Congress and the CDC balked at efforts to prevent people with a travel history to China in early 2020 from coming to the US, the cat was out of the bag. Masks on domestic flights aren't stopping COVID from getting here. The masks don't sanitize anything. Therefore, there is no authority for the mandate.