Nationalism is people of every different race and religion united in one nation they love. It is as appropriate as families are. Do you parents want to live in a commune where your beliefs, traditions, child rearing styles, and family history become a generic meaningless blend of 29, 000 other families? Of course not. You value your family roots and traditions and history and you do it without devaluing anyone elses.
If you thought Nationalism had anything to do with white supremacy or hate its time to walk away from the mainstream news and dunk your head in a vat of dumbass remover.
p.s. for Pete's sake, study American history and learn why there is so much to protect and be proud of here. Enjoy your life here. Or continue to walk around an amazing country being outraged with every damn thing it does but being unable to articulate why (in which case, please refer to vat mention in paragraph 2).
Carry on.