Why do Salafis focus so much on mawlid and not so much on Saudi national day?

Celebrating the mawlid of the best of creation peace and blessings be upon him, his family and his companions, is completely forbidden according to your interpretation of Islam, but celebrating the birth of Saudi Arabia is permitted? Is it bida to be selective about bida? https://riyadhconnect.com/in-pictures-kingdom-makes-worlds-largest-cake-for-saudi-national-day/