Did you know that none of those at the first Thanksgiving were US citizens? 😉 You don't have to be American to give thanks for your blessings, and for the bountiful harvest and for friendship and mutual assistance.
I had a professor in college who was an immigrant and a widower so he often ate with students in the cafeteria. He was fascinated with what people ate at Thanksgiving besides turkey. Although we were a pretty much "white bread" school, there were ethnic differences in what we ate with, or before, the turkey (lasagna, pirogues, sweet pickles, etc.) You can certainly enjoy special occasion foods of your ethnic tradition at Thanksgiving without eating turkey.
Most people throw birthday parties for others and not for themselves.