If we have Columbus Day and Australia Day, why not Henry II Day?

Simon Carswell wrote in the Irish Times: "The arrival of Columbus in the New World led to centuries of exploitation, disease and genocide." For this fact four US states do not mark Columbus Day, instead celebrating Native American Day. President Andrew Jackson whose parents came from Carrickfergus led campaigns against the Creeks and Seminoles during his military career and signed the Indian Removal Act as President. Also in Australia, "Australia Day" celebrates Captain Cook’s arrival there in 1788. Some people now derisively call the holiday "Invasion Day".