For many Imdigenous Americans, Thanksgiving is a day of mourning - The National Day of Mourning is now in its 55th year!!
From the wiki,
The National Day of Mourning is an annual demonstration, held on the fourth Thursday in November, that aims to educate the public about Native Americans in the United States, notably the Wampanoag and other tribes of the Eastern United States; dispel myths surrounding the Thanksgiving story in the United States; and raise awareness toward historical and ongoing struggles facing Native American tribes. The first National Day of Mourning demonstration was held in 1970 after Frank "Wamsutta" James's speaking invitation was rescinded from a Massachusetts Thanksgiving Day celebration commemorating the 350th anniversary of the landing of the Mayflower.