I have a question for Caucasian people who get offended by the term "white."

I have a Lakota friend who is involved in writing up historical markers. She's stuck on the following sentence, and they won't allow her to leave it as is:

"Sitting Bull fought the white people."

She's told it's too offensive. How else are you supposed to describe a battle scene and participants? I don't think "Gold Diggers" or "Terrorists" would go over very well.

They weren't Americans or settlers because it wasn't the USA at the time.

No one can give her any answers. Got any suggestions?

Thanks.